Assay for identifying agents that inhibit chromosome non-disjunction

ABSTRACT

Disclosed is a method of identifying genes whose gene products cause chromosome missegregation. The method involves transfecting a mammalian gene being assessed into a cell and then assessing whether the progeny cells have increased aneuploidy or increased chromosome breaks or translocations compared with cells that have not been transfected with the gene. Genes identified in this manner are likely to be involved in causing diseases such as cancer and Alzheimer&#39;s Disease, which result from improper chromosome segregation. Also disclosed is a method of identifying agents which can be used in the treatment of diseases caused by improper chromosome segregation. The method involves treating cells that have been transfected with a gene whose gene product causes improper chromosome segregation with an agent being assessed. Cells showing less aneuploidy or less chromosomal breakage or translocation compared with untreated cells indicate that the agent is useful in the treatment of diseases caused by improper chromosome segregation.

RELATED APPLICATION

This application is a 371 of PCT/US96/133 14, filed Aug. 15, 1996, which claims the benefit of U.S. Provisional Application No. 60/002,448, filed Aug. 16, 1995.

BACKGROUND OF THE INVENTION

It has been appreciated for some time that Alzheimer's Disease has a complex etiology. At least 15 percent of the cases appear to be due to the inheritance of an autosomal-dominant mutation, but the majority are "sporadic", showing no clear association with any identifiable genetic or environmental factor. Feldman, R. G., et al., Neurology, 13:811-824 1963; Heston, L. L., et al., Arch Gen. Psychiat., 38:1084-1090 (1981); Terry, R. D., Aging, 7:11-14 (1978); Jarvik, L. F. and Matsuyama, S. S., "The Biological Substrates of Alzheimer's Disease", Academic Press, pp. 17-20 (1986). Even identical twins can show a large discordance in the age of onset of the disease. Nee, L. E., et al., Neurology, 37:359-363 (1987). Yet despite this variation, Alzheimer's Disease shows a uniform set of clinical and pathological features--progressive loss of memory and other intellectual functions beginning in middle to late life, coupled with neuronal cell loss in the higher centers of the brain. Price, D. L., Ann. Rev. Neurosci., 9:489-512 (1986).

While much has been learned about the biochemistry and expression of the aberrant protein deposits that characterize Alzheimer's Disease, progress toward the development of methods for the diagnosis and treatment of the disease has been slow. This is due, at least in part, to the fact that the molecular basis for the disease pathology has remained obscure.

SUMMARY OF THE INVENTION

The present invention relates to a method of identifying genes which encode gene products (e.g. proteins and RNA) which cause chromosome missegregation, genes identified by the method, proteins encoded by the genes, antibodies which bind the gene product, a method of identifying agents which reduce (partially or totally) chromosome missegregation in cells, constructs useful in the method of identifying agents which reduce chromosome missegregation in cells, agents identified by the method, methods of preventing chromosome missegregation in cells and agents (including antibodies, peptides, antisense and complementary oligonucleotides and small organic molecules) useful in preventing chromosome missegregation. Also included are genes which hybridize to polynucleotides whose sequences are disclosed herein and which encode proteins which cause chromosome missegregation. As described herein, Applicant has shown that the incidence of trisomy 21 is higher in fibroblasts from individuals with Alzheimer's Disease than in fibroblasts from individuals without Alzheimer's Disease. Based in part on this result, Alzheimer's Disease arises from an accumulation of trisomy 21 cells during the life of the individual, resulting from chromosomal missegregation.

The present invention relates to an assay useful to identify genes whose expression causes chromosome missegregation. Twenty-two genes whose products promoted chromosome missegregation in the yeast assay were isolated from cells obtained from an individual with Alzheimer's Disease. These results provide evidence that genes which give rise to gene products which cause improper chromosome segregation play a role in causing Alzheimer's Disease by promoting the accumulation of trisomy 21 cells. Agents which reduce improper chromosome segregation will slow or inhibit the progression of Alzheimer's Disease.

One embodiment of the present invention is a method of detecting a gene which encodes a gene product which causes chromosome missegregation, thereby resulting in a disease condition. As a result of chromosome missegregation, total chromosome number in the progeny may be greater than, less than or the same as the number of chromosomes in cells in which missegregation does not occur. "Chromosome missegregation" includes processes which result in aneuploid cells, which include cells with an abnormal number of chromosomes. Aneuploid cells include hyperploid cells, which are cells with a greater than normal number of chromosomes, or hypoploid cells, which are cells with a lower than normal number of chromosomes. "Chromosome missegregation" also includes processes which result in chromosomes having one or more breaks or one or more translocations. A chromosome with a translocation is a chromosome which has been broken and recombined with a fragment from a different chromosome.

The method comprises providing cells, referred to as tester cells. Also provided is a plasmid suitable for growth and reproduction in the tester cells. The plasmid comprises 1) a gene obtained from an organism other than yeast, preferably a mammalian gene, referred to as a test gene, whose gene product is suspected of causing chromosome missegregation; and 2) control elements suitable for expressing or overexpressing the test gene in the tester cells. The plasmid is introduced or transfected into the tester cells, which are then exposed to conditions suitable for the tester cells to reproduce, thereby producing progeny cells. The number of aneuploid progeny cells, the number of progeny cells with a chromosome having a break(s) or the number of progeny cells with a chromosome having a translocation is assessed, directly or indirectly, and compared to a suitable control, e.g. progeny cells obtained from the tester cells transfected with a plasmid without the tester gene or having a non-functional tester gene. A greater number of aneuploid progeny cells or a greater number of progeny cells with a chromosome having a break or translocation compared with the control number is indicative that the test gene causes chromosome missegregation.

In a preferred embodiment, the tester cells are yeast cells having one or more chromosomes (preferably one) with a mutated centromere and a marker gene. The mutation in the centromere makes the chromosome(s) prone to improper segregation. The marker gene encodes a detectable/identifiable marker gene product, which gives a quantifiable indication of the number of the mutated chromosome(s) present in the tester cell. The number of aneuploid progeny cells is determined by quantifying the indication given by the marker gene product.

Another embodiment of the present invention is a method of screening for an agent which inhibits improper chromosome segregation. Such an agent is useful in treating a disease caused by a gene product which causes improper chromosome segregation. The method comprises providing tester cells, as described above, transformed with a plasmid suitable for growth and reproduction in the tester cells and comprising 1) a gene which encodes a gene product which causes a disease process as a consequence of improper chromosome segregation resulting in aneuploid cells or cells with one or more chromsomes having a break or a translocation and 2) the appropriate control elements for expressing or over-expressing the gene in the tester cells. The tester cells are exposed to an agent being tested for its ability to inhibit the disease process and to conditions suitable for the tester cells to grow and reproduce, thereby producing progeny cells. The number of aneuploid progeny cells or the number of progeny cells with a chromosome having a break or a translocation is then assessed, either directly or indirectly. A lesser number of aneuploid progeny cells or a lesser number of progeny cells with a chromosome having a break or translocation in the presence of the agent being tested than in the absence of the agent being tested is indicative that the agent inhibits chromosome missegregation.

The present invention can be used to screen for genes which cause Alzheimer's Disease, cancer and aging by promoting improper chromosome segregation. The present invention can also be used to screen for agents which inhibit chromosome missegregation and inhibit disease processes caused by genes encoding gene products which promote chromosome missegregation.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the polynucleotide sequence (SEQ ID NO: 1) of AD3/AD3LP (top line), the amino acid sequence of AD4/AD3L (second line) (SEQ ID NO: 2), the partial polynucleotide sequence of AD3 (bottom line) (SEQ ID NO: 3), the partial amino acid sequence from one reading frame of AD3 (third line) (SEQ ID NO: 4) and the sites of mutation in AD3 (indicated by bold letters immediately below the bottom line). Also shown are the cdc2 kinase motifs of the AD3 and AD4/AD3LP proteins, indicated by boxes.

FIG. 2 is a graph showing the percentage of trisomy 21 cells in cultured fibroblasts from Alzheimer's Disease (AD) and unaffected individuals, as determined by fluorescence in situ hybridization. The greater frequency of trisomy 21 in the Alzheimer fibroblasts is significant at p=0.005.

FIG. 3 is a graph showing the percentage of trisomy 21 cells in cultured fibroblasts, as determined by fluorescence in situ hybridization, for individuals with early onset of Alzheimer's Disease (before age 65 n=7), late onset of Alzheimer's Disease (after age 65 n=5), chromosome 14 linked Alzheimer's Disease (n=12), chromosome 21 linked Alzheimer's Disease (n=2) and unaffected individuals (n=13).

FIG. 4 shows the polydeoxynucleotide sequence of an expressed sequence tag of human mitochondrial tRNA gene (SEQ ID NO: 5) from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 5 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 6) from chromosome 11 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 6 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 7) from chromosome 12 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 7 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 8) from chromosome 12 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 8 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 9) from human laminin receptor on chromosome 3 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 9 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 10) from chromosome 17 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 10 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 11) from human HLABS1 surface antigen on chromosome 6 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 11 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 12) from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 12 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 13) from human H⁺ ATPase subunit B on chromosome 18 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 13 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 14) from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 14 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 15) from chromosome 17 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 15 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 16) from chromosome 17 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 16 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 17) from chromosome 10 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 17 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 18) from human protein kinase C, δ subunit on chromosome 5 of an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 18 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 19) from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 19 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 20) from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 20 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 21) from human histidine tRNA synthase gene on chromosome 9 from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 21 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 22) on chromosome 9 from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 22 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 23) on chromosome 15 from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 23 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 24) from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 24 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 25) from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 25 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 26) from an individual with Alzheimer's Disease. The expressed gene containing the tag was shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 26 shows the polydeoxynucleotide sequence of an expressed sequence tag (SEQ ID NO: 27) for human elongation factor la, shown to cause improper chromosome segregation in the yeast assay of the present invention.

FIG. 27 is a map showing the localization of AD4/AD3LP on chromsome 1 and the yeast artifical chromsomes containing AD4/AD3LP used in the localization.

FIGS. 28A-B show the complete polydeoxynucleotide sequence for AD4/ADLP3 (SEQ ID NO: 28).

FIG. 29 shows the complete amino acid sequence for AD4/ADLP3 (SEQ ID NO: 29).

DETAILED DESCRIPTION OF THE INVENTION

Chromosome missegregation is associated with numerous human disorders. For example, individuals with Down syndrome have an extra chromosome 21, a condition which is referred to as trisomy 21. Alzheimer's Disease is a mosaic form of Down syndrome in which trisomy 21 cells accumulate over life time of the individual. As described herein, fibroblasts from individuals with Alzheimer's Disease show a statistically significant higher percentage of trisomy 21 than fibroblasts from individuals without the disease.

The fibroblasts were derived from individuals with chromosome 14-linked, chromosome 21-linked, early onset, or late onset disease. Increased trisomy 21 was found in all categories of individuals with Alzheimer's Disease examined (see Example 1).

Additional support for the trisomy 21 model of Alzheimer's Disease comes from the observation that individuals with Down syndrome and Alzheimer's Disease have many of the same symptoms. For example, Down syndrome individuals develop the neuropathology associated with Alzheimer's Disease by the fourth decade of life. In addition, Down syndrome individuals are hypersensitive to cholinergic antagonists such as atropine (Sacks and Smith, J. Neurol. Neurosur. and Psych. 52:1294 (1989) and Potter, Am. J. Hum. Genet. 48:1192 (1991). Specifically, when Down syndrome individuals are administered atropine or tropicamide in the eye, their pupils dilate at a lower concentration than is required to dilate the pupil of a normal individual. Alzheimer's individuals are highly sensitive to tropicamide and can be distinguished with 95% confidence from normal individuals or individuals with other neurodegenerative diseases (Scinto et al., Science 266:1051 (1994)).

This model of Alzheimer's Disease supports the conclusion that accumulation of cells with an extra chromosome 21 is caused by a mutated or overexpressed gene or genes which promote chromosome missegregation. "Chromosome non-disjunction," "chromosome missegregation" and "improper chromosome segregation" refer to processes which result in abnormal numbers of chromosomes in at least some members of a cell population. Such a cell is said to be "aneuploid." Cells with greater than normal numbers of chromosomes are "hyperploid", while cells with fewer than normal numbers of chromosomes are "hypoploid". "Chromosome non-disjunction," "chromosome missegregation" and "improper chromosome segregation" also refer to chromosomes with one or more breaks or which have been broken and then recombined with one or more fragments from another chromosome, i.e. the resulting chromosome comprises fragments from one or more fragmented chromosomes. Different genes may be involved in the chromosome missegregation that gives rise to different forms of Alzheimer's Disease, e.g. early onset versus late onset Alzheimer's Disease.

Chromosome missegregation is associated with numerous other human disorders besides Alzheimer's Disease and Down syndrome. Many cancer cells are hyperploid, sometimes at very early stages in the transformation process. Highly aneuploid tumor cells are especially prone to metastasis. Therefore, it is important to identify members of a potential new class of oncogene which, when overexpressed or mutant, causes chromosome missegregation and aneuploidy. Such genes are likely to be oncogenes. Hypoploid cells are also likely to be associated with cancerous tumors.

Elongation factor 1α (EF1α) has been identified as causing chromosome missegregation, using a yeast screen described below. A number of studies have shown the EF1α is overexpressed in many tumors and in cells able to divide in culture, but not in normal tissues of a living organism (Pencil and Nicolson, Breast Cancer Research and Treatments 25:165 (1993)). It has also been shown that overexpression of EF1α makes cells more prone to further transformation by chemical or physical carcinogens such as 3-methyl-cholanthrene or ultraviolet light (Shina et al. Science, 226:282 (1994) and Ghislain et al Nature 366:358 (1993)). Several observed functions of EF1α are consistent with EF1α causing chromosome missegregation. EF1α is an essential component of 26S protease complex, which is necessary for transition into anaphase. In addition, EF1α binds actin filaments and microtubules. It can also nucleate the polymerization of microtubules and has been reported to induce the severing of microtubules both in cell extracts and living cells when present at a high concentration. The latter activity is particularly likely to disrupt the microtubule apparatus of the spindle and lead to chromosome non-disjunction. Thus, it is likely that overexpression of certain genes, e.g. EF1α, or the expression of certain mutated genes cause aneuploidy and provide a necessary oncogenic event in the multistep process of carcinogenesis.

Normal aging also likely involves an increase in chromosome missegregation and the development of aneuploid cells. Therefore, genes identified as causing improper chromosome segregation as a result of mutation or overexpression may underlie the various symptoms of normal aging, in addition to Alzheimer's Disease and cancer.

The present invention is also based on the discovery that a cellular assay system can be used in a method of identifying mammalian genes which cause disease processes by promoting chromosome missegregation. A "disease process" includes a symptom or pathological consequence of a disease. Examples include memory loss and amyloid deposition in Alzheimer's Disease and tumor growth and metastasis in cancer. A gene which "promotes chromosome missegregation" results in significantly more chromosome missegregation when the gene is expressed than when it is not expressed. Such a gene can be a mutated gene which is expressed or wild type gene which is overexpressed. A gene which is "overexpressed" is expressed in amounts sufficiently greater than which normally occurs in the cell such that changes occur in the cell.

The method of the present invention comprises providing tester cells, for example yeast cells, mammalian cells such as human, rat, mouse cells and hamster cells and insect cells. Suitable mammalian cells include lymphoblasts and fibroblast cells.

In one embodiment the tester cells, preferably yeast cells, have a chromosome with a mutant centromere that makes the chromosome prone to improper chromosome segregation (a mutated chromosome) and a first marker gene on the mutated chromosome. A marker gene results in a marker gene product whose concentration is readily determined, either directly or indirectly (e.g. its concentration is proportional to the concentration of another gene product). The concentration of the marker gene product gives an indication of the number of mutant chromosomes; non-disjunctive events which give rise to hyperploidy of the chromosome with the mutated centromere result in increases in the number of marker genes, thereby resulting in increases in the concentration of the marker gene product. Non-disjunctive events which give rise to hypoploidy of the chromosome with the mutated centromere result in a decrease in the number of marker genes, thereby resulting in decreases in the concentration of the marker gene product. The concentration of the marker gene product is directly proportional to the number of chromosomes encoding the marker gene. The assay system can be pre-calibrated, e.g. the concentration of the marker gene product for one, two, three or more copies of the chromosome can be predetermined.

In one example, the first marker gene can give rise to a gene product which enhances or suppresses the expression of a second marker gene. The concentration of the gene product of the second marker gene is therefore proportional (directly or indirectly) to the concentration of the first marker gene product, and therefore proportional to the degree of aneuploidy, e.g. the number of extra chromosomes coding for the first marker gene. Preferably, the concentration of either marker can be assessed by a physical phenomenon which can be readily measured, e.g. color, enzyme assay or antibody detection (e.g. ELISA). The concentration of either marker gene thus indicates the degree of aneuploidy. In another example, the first marker gene product forms a complex with the second marker gene or marker gene product. In this case, the concentration of the complex is an indication of the degree of aneuploidy.

In the assay of the present invention, the tester cells are further modified to screen for mammalian genes which cause chromosome missegregation. Specifically, a mammalian gene, referred to as a test gene, suspected of encoding a product which causes chromosome missegregation, is introduced into the tester cells using an appropriate plasmid vector; the resulting tester cells, which contain the test gene, are maintained under conditions suitable for the gene to be expressed and reproduced by the tester cells. Suitable plasmid vectors typically contain an origin of replication (e.g. an autonomously replicating sequence when the plasmid is transformed into yeast), a yeast centromere and a growth origin suitable for growth and replication in the tester cells being transformed. The plasmid vector also contains a gene allowing for selection in the tester cells being transformed, e.g. a gene conferring resistance to an antibiotic provided in the growth medium (for example amp) or a gene allowing the tester cells to metabolize an essential nutrient supplied in the growth medium (for example trp). Typically, the plasmid also comprises genes suitable for selection and growth in an amplifying organism such as E. Coli, as discussed below. Optionally, the plasmid can contain one or more polycloning sites and/or a gene (e.g. lacz gene) which indicates incorporation of the transforming DNA into the plasmid. Suitable tester cells include yeast, mammalian cells (e.g. human and rodent cells), and insect cells. Plasmids are introduced into the tester cells by methods known in the art, for example electroporation, lithium chloride and by molecules that assist in the introduction of DNA into mammalian cells, such as Transfectam.

Suitable plasmids also have promoter sites which allow the gene being assessed to be expressed in the tester cells (e.g. SV40, gal 10 or other viral promoters). In some cases, it may be desirable to determine whether overexpression of the gene being assessed increases the rate of chromosome missegregation. In these cases, enhancer sites which increase the expression of the gene in the tester cells are also included in the plasmid. The degree of expression can also be increased or decreased by changing the sequence of the promoter site, according to methods known in the art.

In certain applications it may be advantageous to amplify the gene being screened before transforming the tester cells. In this case, the plasmid vector containing the gene is first introduced into an organism (referred to as an "amplifying organism") suitable for amplifying the plasmid. Suitable amplifying organisms include E. coli, gram negative organisms such as Hemophilus influenzae and K. pneumoniae, gram positive organisms such as Bacillus subtilis and eukaryotes such as yeast. The plasmid vector contains a gene suitable for selection in the amplifying organism. The amplifying organism is exposed to suitable growth conditions, thereby allowing the organism to reproduce and amplify the vector. The amplified plasmid vector can then be isolated from the culture and used to transform the tester cells.

After being transformed, the modified tester cells are exposed to conditions suitable for growth and reproduction, thereby producing progeny cells. Typically, a plasmid is used which allows selection of cells into which the plasmid has been incorporated, for example which confers resistance to an antibiotic. The cells are then generally allowed to grow for at least two to three cycles of reproduction before being selected. Cells grown for two to three cycles of reproduction can be analyzed for aneuploidy or chromosomes with breaks or translations, even though the plasmid has not been incorporated into the genome. Alternatively, the selected cells can be treated so that the plasmid is incorporated into the cellular genome, for example, by allowing the selected cells to grow for about 10-20 cycles of reproduction before being analyzed for aneuploid cells or cells with broken or translocated chromosomes.

The degree of aneuploidy in the progeny cells and the number of progeny cells having chromosomes with translocations can be determined by methods known in the art, for example by staining the cells and counting the number of abnormal cells. Methods for staining and determining the number of abnormal cells are disclosed, for example, in Sanchez et al., Lancet 1973:ii:269 (1973), the teachings of which are hereby incorporated herein by reference.

When the tester cells contain a marker gene the degree of aneuploidy is assessed by determining the concentration of one of the marker gene products. This concentration is compared with the concentration of the marker gene product in a suitable control, for example the concentration of the marker gene product in the progeny of tester cells that have been transformed with a plasmid that does not contain the gene being tested for its ability to cause chromosome missegregation. The control can be predetermined, or can be performed simultaneously with or subsequent to the assay which tests the mammalian gene for its ability to cause chromosome missegregation.

A concentration of one of the marker gene products in the progeny cells that differs from the concentration of one of the marker gene products in the control such that there is a greater degree of aneuploidy in the progeny cells than in the control cells indicates that the gene being tested causes chromosome missegregation. Typically, the concentration of one of the marker gene products is determined within subpopulations of progeny cells. A non-disjunction event in a cell will result in aneuploidy being passed on to the progeny of that cell alone. A non-disjunctive event can give rise to hypoploid progeny, hyperploid progeny or both. Consequently, the concentration of the marker gene product will be not be uniform throughout the colonies, but will differ from the control levels only in subpopulations, referred to as "sectors", which are progeny of a cell having undergone chromosome missegregation. Typically, the degree of aneuploidy is assessed by determining the number of sectors throughout the test colony, wherein a larger number of sectors is indicative of a higher degree of aneuploidy. The concentration of marker gene product within the sector and the overall concentration of the marker gene product throughout the test colonies are also indications of the ability of the gene to cause chromosome missegregation.

In a preferred embodiment more than one gene is introduced into the tester cells. It is more preferred that a cDNA library be used to transform the tester cells. The cDNA library is typically obtained from a cell or cells of an individual who has a disease which is believed to arise, at least in part, from a gene causing chromosome non-disjunction. Thus, this preferred embodiment is a method of identifying genes which are involved in disease processes resulting from improper chromosome segregation caused by the genes or their gene products. The cells are grown at low density to keep the progeny of individual clones from overlapping (e.g. about 200 original cells/100 mm plate with augar containing growth medium). Plasmids are recovered from sectors showing marker gene product concentrations which differ from control levels and sequenced. The resulting sequences are from genes which cause chromosome missegregation and are likely involved in the etiology of the disease.

In one example of a suitable assay system, a diploid yeast strain is constructed carrying an ochre mutation in the ade2 gene which determines the color of the yeast colonies grown on plates containing a limited (6 μg/ml) concentration of adenine. This yeast strain is described in Hieter, et al., Cell 40:381 (1985); McGrew, et al., Yeast, 5:271 (1989); Stoler, et al., Genes Dev., 9:573 (1995), the teachings of which are incorporated herein by reference. Cells homozygous for the ochre mutant ade2 gene (ade2-101) are red on these plates. The colonies are changed to pink or white by the presence of either one or two copies respectively of the sup11 gene. Sup11 encodes a suppressor tRNA molecule that can suppress the ochre mutation in the ade2-101 gene and allow production of the ade2 protein product, 5AIR carboxylase, an enzyme involved in purine biosynthesis. The sup11 gene in turn is placed on one specially altered yeast chromosome III that has a mutant centromere (cen130-3) that makes the chromosome prone (100-fold more than normal) to improper chromosome segregation. As a result, this yeast strain shows a high level of variable colored colonies and also colonies in which several colors occur at once to form "sectors." Sectored colonies indicate that during the growth of the colony from a single cell, the instability of the chromosome carrying the sup11 gene results in subclones containing zero, one, or two copies of that chromosome and thus cells which are either red, pink, or white respectively. As these cells divide, their progeny form the multi-colored sectors visible to the naked eye. Under normal conditions, the yeast strain so constructed shows a frequency of chromosome missegregation of about 10⁻⁵ as detected by the color assay (Stoler et al.). However, if a gene encoding a protein that increases chromosome missegregation is introduced into the tester strain, then the frequency of sectored colonies increases. One yeast gene involved in chromosome segregation have been identified in this manner (Stoler et al.).

The above assay was modified to screen for mammalian genes that cause chromosome missegregation, including mutant familial Alzheimer's Disease (FAD) genes. Specifically, a cDNA library was constructed from a human lymphoblastoid cell from a patient with chromosome 14linked FAD using a plasmid vector that can grow in either E. coli or yeast (pRS314.gal1-10). This plasmid contains the CEN6 yeast centromere, the ARSH4 yeast replication origin, a pBR322 origin for growth in E. coli, a trp gene for selection in yeast, an amp gene for selection in E. coli, and a poly-cloning site in the lacz gene. Library DNA was prepared and used to transform E. coli by electroporation (Potter, "Methods in Enzymology: Recombinant DNA Technology," Wu ed. Orlando, Fla., Academic Press, 1993). Cells that received a plasmid were selected by virtue of the ability of the plasmid to provide the trp gene (which is mutant in the yeast strain) and allow the cells to grow in the absence of tryptophan. Transformed cells were plated at relatively low density and the resulting colonies examined for multi-colored sectoring. Sectored colonies were recovered, desegregated into single cells and replated to confirm the cells' high sectoring phenotype. Plasmids were then recovered from the yeast clones showing high sectoring frequency and retransformed into the parent yeast strain to retest the specific cDNA's ability to induce increased chromosome segregation as revealed by sectored colonies.

Following several such sequential screening steps, twenty-two candidate genes were identified. Each gene caused increased levels of chromosome missegregation when expressed in the tester yeast strain and are therefore involved in one way or another in chromosome segregation. The increased chromosome missegregation may be due to overexpression in the target yeast cells of a normal gene involved in chromosome segregation, or to the presence of a mutation in a gene that yields an aberrant protein product that increases chromosome missegregation. Either of these two possibilities may cause the chromosome missegregation observed in the Alzheimer's cells from which the gene's cDNA was derived, and thus all of these twenty-two genes are potential candidates for being a causative agent in the development of Alzheimer's Disease. Partial sequences of these genes are given in FIGS. 4-25.

As described previously, missegregation of chromosomes is involved in the development of a number of different diseases. The assay described above identifies the genes which cause the improper chromosome segregation and, more specifically, genes which cause disease processes as a result of chromosome missegregation. Agents which prevent these genes from causing chromosome missegregation in the assay described above are likely to prevent chromosome missegregation in vivo and theerfore be useful in treating the disease caused by the aberrant gene.

Tester cells containing a chromosome with a mutated centromere, as described above, are particularly useful for identifying agents which inhibit chromosome missegregation. The effect of genes which cause chromosomal missegregation is amplified in these cells and therefore readily detectable. The chromosome with the mutated centromere is more prone to improper segregation than normal yeast chromosomes. When transformed into the tester cells as part of a suitable plasmid, genes which cause chromosomal missegregation cause a detectable change in the concentration of a marker gene product, indicative of a detectable increase in the rate of chromosome non-disjunction. This assay and therefore provides a convenient medium to test agents which inhibit chromosomal missegregation. Agents which decrease the rate of missegregation in tester cells transformed with a gene causing missegregation compared with untransformed tester cells are likely to slow the development of the disease caused by the gene and be useful in the treatment and/or development of treatments of the disease.

Another embodiment of the present invention is a method of identifying an agent which is an inhibitor of a disease process resulting from a gene which causes chromosome missegregation. The method comprises providing tester cells, as described above, additionally comprising a plasmid suitable for growth and reproduction in the tester cells. The plasmid also comprises a gene whose gene product results in the disease process by causing chromosome missegregation resulting in either aneuploid cells or cells with translocated chromosomes. The plasmid also comprises control elements allowing the gene to be expressed in the tester cells. In those cases where overexpression of the gene results in improper chromosome segregation, the plasmid also contains control elements, e.g., an enhancer site, which increases the level of expression of the gene in the tester cells. The tester cells are exposed to an agent being tested for its ability to inhibit the disease process and then to conditions suitable for the cell to grow and reproduce, thereby producing progeny cells. The number of aneuploid progeny cells and the number of progeny cells having translocated chromosomes are then assessed. A lesser number of aneuploid progeny cells or progeny cells having translocated chromosomes in the presence of the agent than in its absence is indicative that the agent inhibits chromosome missegregation and therefore also inhibits the disease process.

A suitable control is, for example, run by allowing tester cells which contain the gene which causes chromosome missegregation to grow and reproduce under the same conditions used in the test assay, but in the absence of the agent being assessed. The number of aneuploid progeny cells and the number of progeny cells with translocations are then assessed and compared to progeny cells grown in the presence of the agent, as described above. The control can be run prior to, simultaneously with or subsequent to the test assay.

There are numerous genes which can be used in the screening assay of the present invention to identify agents which can be used for the treatment of Alzheimer's Disease. For example, locus AD3, associated with susceptibility to early onset of Alzheimer's Disease has recently been mapped to a specific region on human chromosome 14. Five different mis-sense mutations (FIG. 1) have been found that cosegregate with early-onset familial Alzheimer's Disease (Sherrington et al., Nature 375:754 (1995)). It is predicted that these mutations result in increased levels of cells with trisomy 21 in carriers of the mutation compared with non-carriers. As a result, increased levels of chromosome missegregation will be observed when these mutated genes are used in an appropriate plasmid to transform the tester cells used in the assay of the present invention compared with untransformed tester cells. Agents which, when exposed to tester cells, decrease the degree of aneuploidy arising as a result of the expression of these mutated genes are likely to be agents useful in the treatment of Alzheimer's Disease.

It is reported herein that the translation product of the gene (SEQ ID NO: 1 shows a portion of AD4/AD3LP) containing the expressed sequence tag of Accession No. T03796 (Genbank), referred to herein as "AD4/AD3LP" or "Presenilin 2", is highly homologous to AD3 (also referred to as "Presenilin 1") (Sherrington et al., 1995). Confirmation that AD4/AD3LP encodes a novel protein related to AD3 was obtained by genomic mapping. Oligonucleotide primers corresponding to AD4/AD3LP were used for PCR localization of the gene to chromosome 1 rather than chromosome 14, where AD3 resides. Sublocalization using YAC libraries have placed the gene corresponding to AD4/AD3LP to the long arm of chromosome 1, 289 centamorgans from the centromere (see FIG. 27). The complete polynucleotide sequence (SEQ ID NO: 28) and amino acid sequence (SEQ ID NO: 29) of AD4/AD3LP was determined, as described in Example 4.

AD4/AD3LP has four DNA binding motifs (S/T P X X). AP3 also has DNA binding domains. Thus, AD4/AD3LP and AD3 are likely involved in controlling gene expression or in the binding of chromatin to the nuclear membrane. Mutations in chromatin-binding proteins are known to cause chromosome missegregation. Therefore, the observation that AD4/AD3LP and AD3 have DNA binding motifs is consistent with AD4/AD3LP playing a role in causing familial and sporadic forms of Alzheimer's Disease The sites of mutation in AD3 leading to Alzheimer's Disease change amino acids that are identical between AD3 and AD4/AD3LP. For example, FIG. 1 shows the amino acid sequence of AD3, the amino acid sequence from one reading frame of AD4/AD3LP and the amino acid mutations leading to Alzheimer's Disease. It can be seen that the amino acids at these mutated positions in AD3 and the corresponding positions in AD4/AD3LP are identical. This observation coupled with the similarity of AD3 and AD4/AD3LP indicates a similarity of function and is consistent with AD4/AD3LP playing a role in causing familial and sporadic forms of Alzheimer's Disease as a result of mutations similar to those found in AD3. Consequently, AD4/AD3LP can also be used in the screening assay to identify new agents for the treatment of Alzheimer's Disease.

There are numerous genes which can be used in the screening assay of the present invention to identify agents which can be used for the treatment of cancer. For example, overexpression of EF1α, as described earlier, occurs in certain cancers and has been shown to result in highly aneuploid human cells in culture and increased susceptibility to transformation. Introduction of the EF1α gene into yeast and mammalian cells by a plasmid which results in its overexpression causes chromosome missegregation. Agents which reduce the level of chromosome missegregation in these transformed cells can be used in the treatment of cancer in which EF1α is overexpressed.

The twenty-two genes identified in the cellular assay as causing chromosome missegregation are likely to be involved in the development of cancer and Alzheimer's Disease. Consequently, these genes can also be used in the assay described above to screen for agents useful for the treatment of cancer and Alzheimer's Disease. The sequence for the entire gene can be routinely obtained by sequencing the entire plasmid isolated from clones in which non-disjunction is observed. Other genes thought to be involved in the development of Alzheimer's disease such as Apolipoprotein E, for examploe E2, E3 and E4, can also be used in the assay described above to screen for agents useful for the treatment of Alzheimer's Disease.

Another embodiment of the present invention is a polydeoxynucleotide having a sequence represented by SEQ ID NOS: 3, 6-8, 10, 12, 14-17, 19-20 and 22-26. These sequences represent novel polydeoxynucleotides (SEQ ID NOS: 6-8, 10, 12 and 25) or known polydeoxynucleotides with no known function SEQ ID NOS: 3, 14-17, 19-20, 22-24 and 26. Genes comprising these nucleic acids are useful in the assay described above in screening the agents for the treatment of Alzheimer's Disease and cancer and are included in the present invention.

These polydeoxynucelotides have many other uses. One example is as a gene marker, i.e. determining the presence or absence in a sample of the gene to which the a-polydeoxynucleotide hybridizes. The polydeoxynucleotide is labeled, e.g. with a radioactive group or a biotinylated group, and combined with the sample or restricted sample under hybridizing conditions and then amplified by polymerase chain reaction. The presence of the gene is indicated by the presence of labeled, amplified product. Identifying the presence or absence of a gene is particularly useful when the gene or a mutated form of the gene is known to cause a disease. In this instance, identifying the presence or absence of the gene in a sample which contains the genetic material of an individual can be used as a method of diagnosis for the disease. The presence of the form of AD4/AD3LP causing chromosomal missegregation, as described above, is likely to be useful in diagnosing Alzheimer's Disease, both before and after the onset of symptoms typically associated with the disease.

The polydeoxynucleotides of the present invention can also be used for chromosome walking and to assist in determining the nucleotide sequence in the vicinity of the gene, e.g. mapping a chromosome (Singer and Berg, Genes and Genomes, University Science Books, Mill Valley, Calif. (1991)). The chromosome or nucleic acids being mapped are divided into portions two of which are each digested with a different restriction enzyme. The polydeoxynucleotide is used as a probe to identify a fragment from each portion which hybridizes to the probe. The fragments are each sequenced and compared. New non-overlapping sequences can thereby be identified as sequences in the vicinity of the probe.

These polynucleotides are also useful in identifying polymorphic markers such as a sequence repeat. Polymorphic markers are identified by comparing the sequences from the genes of healthy individuals with those from individuals with a disease caused by a mutation in the gene being assessed. Genetic markers can also be identified by sequencing in the vicinity of the gene. Genetic markers can be used in genetic linkage studies, in the mapping of chromosomes and in determining the inheritance of human diseases, including cancer, developmental abnormalities and aging diseases.

Another embodiment of the present invention is a gene which is hybridizable to a polydeoxynucleotide represented by SEQ ID NO: 3, 6-8, 10, 12, 14-17, 19-20 and 22-26. These genes can be obtained by sequencing the entire plasmid from which the polydeoxynucleotide was obtained. These genes have the same uses described above for the polydeoxynucleotides described above. They can also be used for obtaining the genomic gene. A polydeoxydeoxynucleotide comprising the gene is used as a probe to isolate the fragments from a restriction enzyme digest to which it can hybridize. These fragments are then sequenced, thereby identifying regions in the genomic gene, e.g. introns, which do not appear in the cDNA gene.

The invention is further illustrated by the following examples, which are not intended to be limiting in any way.

EXEMPLIFICATION EXAMPLE 1

Individuals with Alzheimer's Disease Have Higher Levels of Trisomy 21 in their Fibroblast Cells than Individuals Without Alzheimer's Disease

Cell Lines--Human fibroblast cell lines were obtained primarily from the NIA Aging Cell Repository (Camden, NJ).

Cell lines containing a mutation in the amyloid precursor is protein were obtained from cells from affected family members by skin biopsy and then grown in culture.

Fluorescence in situ Hybridization (FISH)--Fibroblast cells growing directly on clean, uncoated glass slides were washed with PBS and fixed in cold MeOH: acetic acid, 3:1 for ten minutes. Fixed cells were permeabilized for 15 minutes in 0.5% Triton X-100 and 0.5% saponin in PBS, washed and stored until use in PBS containing 0.2% NaN₃. FISH was carried out according to a modification of the methods described by Lichter et al., Proc. Natl. Acad. Sci. USA, 85:9664 (1988). Slides were denatured in 70% formamide, 2× SSC (1× SSC is 0.15 M NaCl/0.015 M sodium citrate) pH 7.0 at 70° C. for 2 minutes then dehydrated in a cold ethanol series. Denatured probe prepared by nick translation (approximately 10 μg) was applied to the slides in a solution containing 50% formamide, 10% dextran sulphate, 2× SSC, and sheared DNA (herring sperm and Cot I) to block non-specific hybridization (commercially supplied probes were applied in a pre-made solution), cover-slipped, and sealed with rubber cement. Hybridizations were carried out overnight at 37° C. in a humid chamber. Slides were then washed in either 50% formamide in 2× SSC, three times for two minutes each at 42° C. followed by three washes in 0.1× SSC at 60° C., or for two minutes in 2× SSC at 72° C.

Detection of Hybrids--Probes labeled with biotin or digoxigenin were detected using standard immunocytochemistry techniques. Hybridized and washed slides were rinsed in PN (0.1 M NaPO₄, 0.1% Nonidet P40), then incubated with FITC-conjugated avidin (Vector) or FITC-conjugated antidigoxigenin (Boehringer). After washing three times for two minutes each in PN, mounting medium containing propidium iodide (a red fluorescing DNA dye) or DAPI (a blue fluorescing DNA dye) and an antifade reagent was applied and coverslips mounted.

Identifying labels on the slides were replaced with anonymous codes before being given to an observer to count the number of chromosomes 21 per nucleus. Slides were evaluated using a Zeiss Axiophot equipped with a mercury lamp and a 63× objective. An average of 800 nuclei were analyzed per cell line.

Hybridization Probes--Biotinylated or digoxigenin-labeled chromosome 21-specific probes were either commercially obtained (Oncor) or generated using a cosmid containing a 21-specific sequence. The cosmid was labeled by nick translation with biotinylated dATP.

Calculation of Trisomy Percentages--Not all chromosomes hybridize in the FISH procedure. Therefore it was necessary to correct for the number of false trisomies caused by under-hybridization of cells that were in the G2 phase of the cell cycle and so were actually tetrasomic.

The following formula was developed to estimate the real number of trisomies present in fibroblast cultures using only the assumptions that each chromosome in a nucleus hybridizes as an independent event and all observed monosomies are actually disomies in which one chromosome failed to hybridize. ##EQU1## Where M=observed % monosomies, d=observed % disomies, t=observed % trisomies, and q=observed % tetrasomies

Results

Table I and FIG. 2 show the percent trisomy 21 observed by FISH in fibroblast cultures of 39 Alzheimer's Disease patients and unaffected individuals. The overall average amount of trisomy 21 was 5.5% in Alzheimer's Disease cultures and 2.5% in cultures from unaffected individuals. Using the same procedure, the number of trisomies in a Down syndrome culture was determined to be 98%. The greater frequency of trisomy 21 cells in Alzheimer's Disease patients is significant (p=0.005) and is not related to the age of the affected individuals. It is unlikely that there is a general influence of time in culture on the degree of aneuploidy as this is varied in both control and Alzheimer's Disease cultures, and it has been found that human fibroblasts remain largely euploid throughout their lifetime in culture (Hayflick and Moorehead, Exp. Cell. Res. 25:585 (1961)).

The Alzheimer's Disease cultures were derived from individuals with chromosome 14-linked, chromosome 21linked, early onset, or late onset disease. It is of interest to know whether the trisomies were confined only to individuals in specific categories. FIG. 3 shows that there is increased trisomy 21 in all categories of Alzheimer's Disease cultures compared to cultures from unaffected individuals. The individuals with chromosome 14-linked Alzheimer's Disease were from the large Canadian, Italian, and German pedigrees and had an average trisomy 21 frequency of 3.7t. Only two individuals with chromosome 21 linked Alzheimer's Disease were examined and they exhibited 4% and 5% trisomy 21. Individuals with early- and late-onset disease had distinctly elevated levels of trisomy 21 compared to unaffected controls. Their average trisomy 21 frequencies were 8.5% and 5.8%, respectively as compared to the unaffected individuals (2.5%). In these latter groups, insufficient family data were available to determine whether they were familial or sporadic cases of Alzheimer's Disease.

These results indicate that several different mechanisms causing Alzheimer's Disease, both familial and sporadic (which includes complex genetic and/or environmental effects), may directly induce trisomy 21 via chromosome nondisjunction. The effect of nondisjunction could be restricted to chromosome 21 alone, but more likely involves other, perhaps all, chromosomes as well. The effect of non-disjunction on other chromosomes can be determined by using the procedures described above with probes specific for the other chromosomes.

                  TABLE I                                                          ______________________________________                                                                # of Nuclei                                               Culture Name AD Status Analyzed % Trisomy                                    ______________________________________                                         0364D     AD/early     195        18.9                                           4159 AD/chr. 14 505 2.2                                                        4400A AD/early 1481 1.3                                                        4402A AD/early 937 6.7                                                         5770 AD/early 517 4.6                                                          5809 AD/early 225 21                                                           5810C AD/late 136 10.5                                                         6840B AD/chr. 14 840 3.8                                                       6844 AD/chr. 14 1144 3.6                                                       6848B AD/chr. 14 1001 2.9                                                      7375 AD/early 1115 4.9                                                         7377A AD/early 502 2.2                                                         7872 AD/chr. 14 1938 4.7                                                       8110 AD/chr. 14 321 4.3                                                        8170A AD/chr. 14 1026 1.9                                                      8243 AD/late 500 6.9                                                           8245 AD/late 719 6.9                                                           8446 AD/chr. 14 1063 4.8                                                       8523 AD/chr. 14 614 5.4                                                        8527 AD/chr. 14 570 6.4                                                        8563A AD/chr. 14 501 3.3                                                       8597 AD/chr. 14 502 1.3                                                        9908 AD/late 500 1.3                                                           10788 AD/late 498 3.4                                                          CG AD/chr. 21 481 3.7                                                          H010 AD/chr. 21 479 5.2                                                        8942 Down syndrome 1515 98.3                                                   2602 Unaffected 853 3.9                                                        4153 Unaffected 1017 2.9                                                       7615 Unaffected 195 4.1                                                        7865 Unaffected 1540 1.0                                                       7871 Unaffected 336 2.1                                                        8125 Unaffected 505 2.6                                                        8379 Unaffected 508 3.8                                                        8517 Unaffected 485 1.1                                                        8620 Unaffected 1117 2.7                                                       8701 Unaffected 509 3.9                                                        8712 Unaffected 508 0.9                                                        9173 Unaffected 612 0.5                                                        Swedish 2 Unaffected 513 3.4                                                 ______________________________________                                          Culture names are those assigned by the Coriell Cell Repository with the       exception of CG and DH, which are lines from M. Benson, and Swedish 2          which is an unaffected member of a Swedish family carrying an APP              mutation. Lines identified as Chr. 21 and Chr. 14 are from individuals         whose Alzheimer's Disease has been linked to those chromosomes. Early and      late refer to the apparent early (before age 65) and late (after age 65)       age of onset of Alzheimer's Disease in individuals  # whose disease is         either familial with no specific chromosomal linkage identified or             apparently sporadic.                                                     

EXAMPLE 2

Assay for Identifying Genes Causing Chromosome Non-Disjunction

SBD8 is a yeast strain of the genotype a/α, ade2-101/ade2-101, HIS3+/-, leu2-/-, lys2-/-, trp1-/-, ura3+/-, CEN3SUP11:cen130-3:URA3 (Stoler et al.)

PRS314.GAL1-10 is a TRP1 plasmid constructed from the original pRS314 of Hieter et al., Cell, 40:381 (1985). It contains the GA/10 UAS in the RI/BAM site of the polylinker and is induced on 2% nonautoclaved galactose. The GAl1/10 UAS is repressed on 5-10% glucose.

AG09371 (GU3908) is a lymphoblastoid cell line from an affected member of a familial Alzheimer's Disease pedigree (termed FAD3, in St. George-Hyslop et al., Science, 235:885 (1987), which incorrectly identified the family as harboring a mutant gene on chromosome 21. The family has subsequently been identified as a chromosome 14 familial Alzheimer's Disease family (Schellenberg, et al., Science, 258:668 (1992); St. George-Hyslop et al., Nature Genet. 2:330 (1992)). This is a Russian-Jewish pedigree containing 23 affected individuals. The cell line AG09371 is from the NIA aging cell repository sponsored by the National Institute on Aging and located at the Coriell Institute for Medical Research in Camden, N.J. GUS3908 is the Massachusetts General Hospital cell number.

Library Construction

PolyA+ mRNA was isolated from 2×108 cells of a lymphoblastoid line (AG09371) from a familial Alzheimer's Disease patient using the FASTTRACK kit (Pharmacia). Full-length cDNA primed with oligoDT-containing primers was carried out using the SUPERSCRIPT cDNA library kit (Gibco-BRL) according to manufacturer's instructions. The resulting full-length cDNA (above 500 nucleotides in length) was ligated into the pRS314.gal1-10 vector using the BamH1 and Not1 sites to ensure directional cloning. The resulting plasmids were used to transform K-12 E. coli strain by electroporation (Potter, 1993) and plated on large (150 mm), amp-containing plates to amplify the library. DNA was prepared from the transformed bacteria by the Qiagen column method. Library DNA was used to transform SBD8 yeast cells by the lithium chloride method. Transformants were plated on plates lacking tryptophan and containing 6 μg/ml adenine at a concentration of about 500 cells/100 mm plate. Sectored colonies were visually screened by the method below, taken from Stoler et al. (1995).

Yeast Colony Screening

The mitotic segregation of SUP11-marked chromosomes bearing cen130-3 centromeres was monitored using the color colony assay on limiting adenine media (Hieter et al., 1985). SUP11 partially suppresses the red color phenotype of ade2-101 yeast cells. Hence, in a diploid yeast cell homozygous for the ade2-101 allele, one copy of SUP11 suppresses partially the red color to form homogeneous pink colonies. Two copies of SUP11 suppress fully this phenotype resulting in white colonies. Strains where SUP11 is linked genetically to a chromosome that is mitotically unstable form colonies that contain red, pink and white sectors. Red and pink sectors arise from chromosome loss (1:0) events and nondisjunction (2:0) events result in red/white sectors. Half-sectored colonies represent missegregation events that occurred at the first division after plating. The number of half-sectored colonies divided by the total number of mostly pink colonies plated represents the mis-segregation frequency of the SUP11-bearing chromosome. In addition, the number of red/pink and red/white half-sectored colonies is used to determine the frequency of chromosome loss or nondisjunction, respectively. The mis-segregation data from cen130-3 chromosomes was collected as follows. In each assay, three mostly pink colonies were picked from color media plates and about 3000 cells were spread onto large (150×15 mm) color media plates, incubated for 4 days at 30° C. and then overnight at 4° C. At least three independent assays were performed to monitor the segregation of cen130-3 chromosomes in each wild-type and cse4-1 strain.

DNA Analysis

Following multiple transformation and sector colony screening, twenty-two cDNAs were identified which continuously cause chromosome nondisjunction and sectored colonies in the transformed yeast cells. DNA prepared from twenty-two E. coli strains harboring the individual candidate human cDNA recombinant plasmids was then subjected to dideoxy sequencing analysis. Several known genes were among the candidates, including HLAB51, protein kinase C-δ, and elongation factor 1a. In addition, a number of unknown genes were identified. All sequences were mapped to their respective human chromosomes by PCR analysis of mapped YAC libraries and/or human-rodent somatic cell hybrid lines. Partial sequences are shown in FIGS. 4-26.

The plasmids isolated above containing polynucleotides corresponding to SEQ ID NOS: 6, 15, 19, 20 22, 24 and 26 were re-transfected into SBD8 yeast cells as described above. The nondisjunctive frequency for each transformation was then determined, as described above. Yeast transformed with genes corresponding to SEQ ID NOS: 6, 15, 19, 20 22, 24 and 26 showed an increase in the frequency of nondisjunction of 2.7 (standard deviation=1.92), 2.4 (standard deviation=1.74), 3.1 (standard deviation=3.17), 3.7 (standard deviation=3.21), 3.7 (standard deviation=2.1) and 3.3 (standard deviation=1.98) fold, respectively, compared with yeast transformed with the pRS314.gal1-10 vector alone.

EXAMPLE 3

AD3 and AD4/AD3LP Increase the Frequency of Chromosome Nondisjunction in cDNA Transfected Lymphoblasts

The AD3 gene was obtained as described in Sherrington et al., Nature 375:754 (1995); the AD4/AD3LP gene obtained as described above. These genes were ligated into the pcDNA3 vector purchased from Invitrogen, Inc. according to procedures disclosed in "Current Protocols in Molecular Biology", John Wiley & Sons (1989) and transfected into lymphoblasts with normal karyotypes by electroporation techniques disclosed in Potter, "Methods in Enzymology: Recombinant DNA Technology," Wu ed. Orlando, Fla., Academic Press, 1993). Untransfected control cells and control cells transfected with unmodified pcDNA3 vector were also prepared. The cells were then allowed to grow for about sixty hours and the frequency of nondisjunction determined by methods disclosed in Sanchez et al., Lancet 1973:ii:269 (1973). The results are shown in Table II below:

                  TABLE II                                                         ______________________________________                                         CHROMOSOME NONDISJUNCTION TEST IN cDNA                                           TRANSFECTED LYMPHOBLAST                                                      ______________________________________                                         H.sub.2 O                                                                                               Total No. of                                            Expt# Count* Cells Count/Tot                                                 ______________________________________                                           1 2 20 0.10                                                                    2 0 17 0.00                                                                    3 4 25 0.16                                                                  ______________________________________                                         pcDNA3                                                                                         Total No.          Ratio to                                       Count* of Cells Count/Tot H.sub.2 O                                         ______________________________________                                           1 0 20 0.00 0.00                                                               2                                                                              3 2 24 0.08 0.52                                                             ______________________________________                                          *Total number of aneuploid cells or cells with broken or translocated          chromosomes.                                                             

Cells transfected with the AD3 gene or the AD4/AD3LP gene were found to have an increased frequency of nondisjunction compared with control cells.

EXAMPLE 4

Determination of the Entire Polynucleotide and Amino Acid Sequence of AD4/AD3LP

Identification of T03796 and Cloning of the Full-Length cDNA--All nucleotide sequences in the GenBank data base were translated into amino acid sequences in all six reading frames and then compared to the published protein sequence (24) of AD3 (S182), by using TBLASTIN (National Center for Biotechnology Information server). The expressed sequence tag (EST) sequence (T03796) whose encoded protein was most highly homologous to AD3 was thus identified, and the corresponding cDNA clone was obtained from the Lawrence Livermore National Laboratory (IMAGE Consortium). After we had determined the full sequence of T03796 (see below), additional EST sequences identical to T03796 (GenBank accession nos. R16831 and R05822) were also identified. Because all of these EST clones were partial, 5' rapid amplification of cDNA ends (RACE) was used to complete the full-length cDNA corresponding to T03796.

Sequencing and Analysis of DNA and Encoded Proteins--The T03796 sequence in GenBank consists of 476 nt, with some errors. We resequenced the reported region and then sequenced the rest of T03796 and the 5' RACE clones for a total of 2.4 kb. DNA sequencing was carried out by the dideoxynucleotide china-terminating procedure with fluorescent-tag-labeled deoxynucleotides by the Biopolymer Laboratory, Harvard Medical School. Oligonucleotide primers used for sequencing were also synthesized by the Biopolymer Laboratory. Sequences were compared for homology to other sequences in the GenBank, GenEMBL, and dbest data bases, by using FASTA (GCG software package from the Wisconsin Genetics Computer Group) and by BLASTIN and BLASTIN (National Center for Biotechnology Information server).

Equivalents

Those skilled in the art will know, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. These and all other equivalents are intended to be encompassed by the following claims.

    __________________________________________________________________________     #             SEQUENCE LISTING                                                    - -  - - (1) GENERAL INFORMATION:                                              - -    (iii) NUMBER OF SEQUENCES: 29                                           - -  - - (2) INFORMATION FOR SEQ ID NO:1:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 1417 base - #pairs                                                 (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -     (ix) FEATURE:                                                                   (A) NAME/KEY: CDS                                                              (B) LOCATION: 2..1129                                                 - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:1:                - - G AGA ATT CCC TTG CGG CCG ACA GGC CTG GAG - #GAA GAG CTG ACC CTC              46                                                                           Arg Ile Pro Leu Arg Pro Thr Gly Leu G - #lu Glu Glu Leu Thr Leu                  1              - # 5                 - # 10                 - # 15          - - AAA TAC GGA GCG AAG CAC GTG ATC ATG CTG TG - #T GTG CCT GTC ACT CT             94                                                                        Lys Tyr Gly Ala Lys His Val Ile Met Leu Cy - #s Val Pro Val Thr Leu                             20 - #                 25 - #                 30               - - TGC ATG ATC GTG GTG GTA GCC ACC ATC AAG TC - #T GTG CGC TTC TAC ACA           142                                                                        Cys Met Ile Val Val Val Ala Thr Ile Lys Se - #r Val Arg Phe Tyr Thr                         35     - #             40     - #             45                   - - GAG AAG AAT GGA CAG CTC ATC TAC ACG CCA TT - #C ACT GAG GAC ACA CCC           190                                                                        Glu Lys Asn Gly Gln Leu Ile Tyr Thr Pro Ph - #e Thr Glu Asp Thr Pro                     50         - #         55         - #         60                       - - TCG GTG GGC CAG CGC CTC CTC AAC TCC GTG CT - #G AAC ACC CTC ATC ATG           238                                                                        Ser Val Gly Gln Arg Leu Leu Asn Ser Val Le - #u Asn Thr Leu Ile Met                 65             - #     70             - #     75                           - - ATC AGC GTC ATC GTG GTT ATG ACC ATC TTC TT - #G GTG GTG CTC TAC AAG           286                                                                        Ile Ser Val Ile Val Val Met Thr Ile Phe Le - #u Val Val Leu Tyr Lys             80                 - # 85                 - # 90                 - # 95        - - TAC CGC TGC TAC AAG TTC ATC CAT GGG TGG TT - #G ATC ATG TCT TCA CTG           334                                                                        Tyr Arg Cys Tyr Lys Phe Ile His Gly Trp Le - #u Ile Met Ser Ser Leu                            100  - #               105  - #               110               - - ATG CTG CTG TTC CTC TTC ACC TAT ATC TAC CT - #T GGG GAA GTG CTC AAG           382                                                                        Met Leu Leu Phe Leu Phe Thr Tyr Ile Tyr Le - #u Gly Glu Val Leu Lys                        115      - #           120      - #           125                   - - ACC TAC AAT GTG GCC ATG GAC TAC CCC ACC CT - #C TTG CTG ACT GTC TGG           430                                                                        Thr Tyr Asn Val Ala Met Asp Tyr Pro Thr Le - #u Leu Leu Thr Val Trp                    130          - #       135          - #       140                       - - AAC TTC GGG GCA GTG GGG CAT GGT GTG ATC CA - #C TGG AAG GGC CCT CTG           478                                                                        Asn Phe Gly Ala Val Gly His Gly Val Ile Hi - #s Trp Lys Gly Pro Leu                145              - #   150              - #   155                           - - GTG CTG GAG CAG GCC TAC CTC ATC ATG ATC AG - #T GCG CTC ATG CCC CTA           526                                                                        Val Leu Glu Gln Ala Tyr Leu Ile Met Ile Se - #r Ala Leu Met Pro Leu            160                 1 - #65                 1 - #70                 1 -       #75                                                                               - - ATG TTC ATC AAG TAC CCT CCA GAG TGG TCC GC - #G TGG GTG ATC CTG         GCG      574                                                                     Met Phe Ile Lys Tyr Pro Pro Glu Trp Ser Al - #a Trp Val Ile Leu Ala                           180  - #               185  - #               190               - - CCC ATC TCT GTG TAT GAT CTC GTG ACT GTC CT - #G TGT TCC ACA GGG CCT           622                                                                        Pro Ile Ser Val Tyr Asp Leu Val Thr Val Le - #u Cys Ser Thr Gly Pro                        195      - #           200      - #           205                   - - CTG AGA ATG CTG GTA GAA ACT GCC CAG GAG AG - #A AAT GAG ACC ATA TTC           670                                                                        Leu Arg Met Leu Val Glu Thr Ala Gln Glu Ar - #g Asn Glu Thr Ile Phe                    210          - #       215          - #       220                       - - TCT CCC CTG ATA TAC TCA TCT CCC ATG GTG TG - #G ACG GTT GTC ATG TCG           718                                                                        Ser Pro Leu Ile Tyr Ser Ser Pro Met Val Tr - #p Thr Val Val Met Ser                225              - #   230              - #   235                           - - AAG CTG GAC CCC TCC TCT CAG GGT GCC CTC CA - #G CTC CCC TAC GAC CCG           766                                                                        Lys Leu Asp Pro Ser Ser Gln Gly Ala Leu Gl - #n Leu Pro Tyr Asp Pro            240                 2 - #45                 2 - #50                 2 -       #55                                                                               - - GAG ATG GAA GAC TCC TAT GAC AGT TTT GGG GA - #G CCT TCA TAC CCC         GAA      814                                                                     Glu Met Glu Asp Ser Tyr Asp Ser Phe Gly Gl - #u Pro Ser Tyr Pro Glu                           260  - #               265  - #               270               - - GTC TTT GAG CCT CCC CTG GCT GGC TAC CCA GG - #G GAG GAG CTG GAG GAA           862                                                                        Val Phe Glu Pro Pro Leu Ala Gly Tyr Pro Gl - #y Glu Glu Leu Glu Glu                        275      - #           280      - #           285                   - - GAG GAG GAA AGT CAA GGG GGC GTG AAG CTT GT - #C CTC GGG ACT TCA ACT           910                                                                        Glu Glu Glu Ser Gln Gly Gly Val Lys Leu Va - #l Leu Gly Thr Ser Thr                    290          - #       295          - #       300                       - - TCC ACA GTT GTT CCT GGT GGC CAA GCG CCT CC - #C ACG GGC AGC GGG GAC           958                                                                        Ser Thr Val Val Pro Gly Gly Gln Ala Pro Pr - #o Thr Gly Ser Gly Asp                305              - #   310              - #   315                           - - TGG ATA ACC ACG CTG GCC TGC TTC GTG GCC AT - #C CTC ATT GGC TTG TGT          1006                                                                        Trp Ile Thr Thr Leu Ala Cys Phe Val Ala Il - #e Leu Ile Gly Leu Cys            320                 3 - #25                 3 - #30                 3 -       #35                                                                               - - CTG ACC CTC CTG CTG CTT GCT GTG TTC AAG AA - #G GCG CTG CCC GCC         CTC     1054                                                                     Leu Thr Leu Leu Leu Leu Ala Val Phe Lys Ly - #s Ala Leu Pro Ala Leu                           340  - #               345  - #               350               - - CCC ATC TCC ATC ACG TTC GGG CTC ATC TTT TA - #C TTC TCC ACG GAC AGG          1102                                                                        Pro Ile Ser Ile Thr Phe Gly Leu Ile Phe Ty - #r Phe Ser Thr Asp Arg                        355      - #           360      - #           365                   - - AAG CAC AGC AGG TTT ATC CAG ATG AAC TGAGAAGGT - #C AGATTAGGGC                1149                                                                        Lys His Ser Arg Phe Ile Gln Met Asn                                                    370          - #       375                                              - - GGGGAGAAGA GCATCCGGCA TGAGGGCTGA GATGCGCAAA GAGTGTGCTC GG -              #GAGTGGCC   1209                                                                  - - CCTGGCACCT GGGTGCTCTG GCTGGAGAGG AAAAACCAGT TCCCTACGAG GA -             #GTGTTCCC   1269                                                                  - - AATGCTTTGT CCATGATGTC CTTGTTATTT TATTGCCTTT AGAAACTGAG TC -             #CTGTTCTT   1329                                                                  - - GTTACGGCAG TCACACTGCT GGGAAGTGGC TTAATACTAA TATCAATAAA TA -             #GATGAGTC   1389                                                                  - - CTGTTAGAAA AAAAAAAAAA AAAAAAAA         - #                  - #                1417                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:2:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 376 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -                   - #(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:               - - Arg Ile Pro Leu Arg Pro Thr Gly Leu Glu Gl - #u Glu Leu Thr Leu Lys         1               5 - #                 10 - #                 15               - - Tyr Gly Ala Lys His Val Ile Met Leu Cys Va - #l Pro Val Thr Leu Cys                    20     - #             25     - #             30                   - - Met Ile Val Val Val Ala Thr Ile Lys Ser Va - #l Arg Phe Tyr Thr Glu                35         - #         40         - #         45                       - - Lys Asn Gly Gln Leu Ile Tyr Thr Pro Phe Th - #r Glu Asp Thr Pro Ser            50             - #     55             - #     60                           - - Val Gly Gln Arg Leu Leu Asn Ser Val Leu As - #n Thr Leu Ile Met Ile        65                 - # 70                 - # 75                 - # 80        - - Ser Val Ile Val Val Met Thr Ile Phe Leu Va - #l Val Leu Tyr Lys Tyr                        85 - #                 90 - #                 95               - - Arg Cys Tyr Lys Phe Ile His Gly Trp Leu Il - #e Met Ser Ser Leu Met                   100      - #           105      - #           110                   - - Leu Leu Phe Leu Phe Thr Tyr Ile Tyr Leu Gl - #y Glu Val Leu Lys Thr               115          - #       120          - #       125                       - - Tyr Asn Val Ala Met Asp Tyr Pro Thr Leu Le - #u Leu Thr Val Trp Asn           130              - #   135              - #   140                           - - Phe Gly Ala Val Gly His Gly Val Ile His Tr - #p Lys Gly Pro Leu Val       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Leu Glu Gln Ala Tyr Leu Ile Met Ile Ser Al - #a Leu Met Pro Leu         Met                                                                                              165  - #               170  - #               175              - - Phe Ile Lys Tyr Pro Pro Glu Trp Ser Ala Tr - #p Val Ile Leu Ala Pro                   180      - #           185      - #           190                   - - Ile Ser Val Tyr Asp Leu Val Thr Val Leu Cy - #s Ser Thr Gly Pro Leu               195          - #       200          - #       205                       - - Arg Met Leu Val Glu Thr Ala Gln Glu Arg As - #n Glu Thr Ile Phe Ser           210              - #   215              - #   220                           - - Pro Leu Ile Tyr Ser Ser Pro Met Val Trp Th - #r Val Val Met Ser Lys       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Leu Asp Pro Ser Ser Gln Gly Ala Leu Gln Le - #u Pro Tyr Asp Pro         Glu                                                                                              245  - #               250  - #               255              - - Met Glu Asp Ser Tyr Asp Ser Phe Gly Glu Pr - #o Ser Tyr Pro Glu Val                   260      - #           265      - #           270                   - - Phe Glu Pro Pro Leu Ala Gly Tyr Pro Gly Gl - #u Glu Leu Glu Glu Glu               275          - #       280          - #       285                       - - Glu Glu Ser Gln Gly Gly Val Lys Leu Val Le - #u Gly Thr Ser Thr Ser           290              - #   295              - #   300                           - - Thr Val Val Pro Gly Gly Gln Ala Pro Pro Th - #r Gly Ser Gly Asp Trp       305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - Ile Thr Thr Leu Ala Cys Phe Val Ala Ile Le - #u Ile Gly Leu Cys         Leu                                                                                              325  - #               330  - #               335              - - Thr Leu Leu Leu Leu Ala Val Phe Lys Lys Al - #a Leu Pro Ala Leu Pro                   340      - #           345      - #           350                   - - Ile Ser Ile Thr Phe Gly Leu Ile Phe Tyr Ph - #e Ser Thr Asp Arg Lys               355          - #       360          - #       365                       - - His Ser Arg Phe Ile Gln Met Asn                                               370              - #   375                                                  - -  - - (2) INFORMATION FOR SEQ ID NO:3:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 1488 base - #pairs                                                 (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -     (ix) FEATURE:                                                                   (A) NAME/KEY: CDS                                                              (B) LOCATION: 2..1222                                                 - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:3:                 - - G CAG GTG GTG GAG CAA GAT GAG GAA GAA GAT - #GAG GAG CTG ACA TTG              46                                                                           Gln Val Val Glu Gln Asp Glu Glu Glu A - #sp Glu Glu Leu Thr Leu                  1              - # 5                 - # 10                 - # 15          - - AAA TAT GGC GCC AAG CAT GTG ATC ATG CTC TT - #T GTC CCT GTG ACT CTC            94                                                                        Lys Tyr Gly Ala Lys His Val Ile Met Leu Ph - #e Val Pro Val Thr Leu                             20 - #                 25 - #                 30               - - TGC ATG GTG GTG GTC GTG GCT ACC ATT AAG TC - #A GTC AGC TTT TAT ACC           142                                                                        Cys Met Val Val Val Val Ala Thr Ile Lys Se - #r Val Ser Phe Tyr Thr                         35     - #             40     - #             45                   - - CGG AAG GAT GGG CAG CTA ATC TAT ACC CCA TT - #C ACA GAA GAT ACC GAG           190                                                                        Arg Lys Asp Gly Gln Leu Ile Tyr Thr Pro Ph - #e Thr Glu Asp Thr Glu                     50         - #         55         - #         60                       - - ACT GTG GGC CAG AGA GCC CTG CAC TCA ATT CT - #G AAT GCT GCC ATC ATG           238                                                                        Thr Val Gly Gln Arg Ala Leu His Ser Ile Le - #u Asn Ala Ala Ile Met                 65             - #     70             - #     75                           - - ATC AGT GTC ATT GTT GTC ATG ACT ATC CTC CT - #G GTG GTT CTG TAT AAA           286                                                                        Ile Ser Val Ile Val Val Met Thr Ile Leu Le - #u Val Val Leu Tyr Lys             80                 - # 85                 - # 90                 - # 95        - - TAC AGG TGC TAT AAG GTC ATC CAT GCC TGG CT - #T ATT ATA TCA TCT CTA           334                                                                        Tyr Arg Cys Tyr Lys Val Ile His Ala Trp Le - #u Ile Ile Ser Ser Leu                            100  - #               105  - #               110               - - TTG TTG CTG TTC TTT TTT TCA TTC ATT TAC TT - #G GGG GAA GTG TTT AAA           382                                                                        Leu Leu Leu Phe Phe Phe Ser Phe Ile Tyr Le - #u Gly Glu Val Phe Lys                        115      - #           120      - #           125                   - - ACC TAT AAC GTT GCT GTG GAC TAC ATT ACT GT - #T GCA CTC CTG ATC TGG           430                                                                        Thr Tyr Asn Val Ala Val Asp Tyr Ile Thr Va - #l Ala Leu Leu Ile Trp                    130          - #       135          - #       140                       - - AAT TTT GGT GTG GTG GGA ATG ATT TCC ATT CA - #C TGG AAA GGT CCA CTT           478                                                                        Asn Phe Gly Val Val Gly Met Ile Ser Ile Hi - #s Trp Lys Gly Pro Leu                145              - #   150              - #   155                           - - CGA CTC CAG CAG GCA TAT CTC ATT ATG ATT AG - #T GCC CTC ATG GCC CTG           526                                                                        Arg Leu Gln Gln Ala Tyr Leu Ile Met Ile Se - #r Ala Leu Met Ala Leu            160                 1 - #65                 1 - #70                 1 -       #75                                                                               - - GTG TTT ATC AAG TAC CTC CCT GAA TGG ACT GC - #G TGG CTC ATC TTG         GCT      574                                                                     Val Phe Ile Lys Tyr Leu Pro Glu Trp Thr Al - #a Trp Leu Ile Leu Ala                           180  - #               185  - #               190               - - GTG ATT TCA GTA TAT GAT TTA GTG GCT GTT TT - #G TGT CCG AAA GGT CCA           622                                                                        Val Ile Ser Val Tyr Asp Leu Val Ala Val Le - #u Cys Pro Lys Gly Pro                        195      - #           200      - #           205                   - - CTT CGT ATG CTG GTT GAA ACA GCT CAG GAG AG - #A AAT GAA ACG CTT TTT           670                                                                        Leu Arg Met Leu Val Glu Thr Ala Gln Glu Ar - #g Asn Glu Thr Leu Phe                    210          - #       215          - #       220                       - - CCA GCT CTC ATT TAC TCC TCA ACA ATG GTG TG - #G TTG GTG AAT ATG GCA           718                                                                        Pro Ala Leu Ile Tyr Ser Ser Thr Met Val Tr - #p Leu Val Asn Met Ala                225              - #   230              - #   235                           - - GAA GGA GAC CCG GAA GCT CAA AGG AGA GTA TC - #C AAA AAT TCC AAG TAT           766                                                                        Glu Gly Asp Pro Glu Ala Gln Arg Arg Val Se - #r Lys Asn Ser Lys Tyr            240                 2 - #45                 2 - #50                 2 -       #55                                                                               - - AAT GCA GAA AGC ACA GAA AGG GAG TCA CAA GA - #C ACT GTT GCA GAG         AAT      814                                                                     Asn Ala Glu Ser Thr Glu Arg Glu Ser Gln As - #p Thr Val Ala Glu Asn                           260  - #               265  - #               270               - - GAT GAT GGC GGG TTC AGT GAG GAA TGG GAA GC - #C CAG AGG GAC AGT CAT           862                                                                        Asp Asp Gly Gly Phe Ser Glu Glu Trp Glu Al - #a Gln Arg Asp Ser His                        275      - #           280      - #           285                   - - CTA GGG CCT CAT CGC TCT ACA CCT GAG TCA CG - #A GCT GCT GTC CAG GAA           910                                                                        Leu Gly Pro His Arg Ser Thr Pro Glu Ser Ar - #g Ala Ala Val Gln Glu                    290          - #       295          - #       300                       - - CTT TCC AGC AGT ATC CTC GCT GGT GAA GAC CC - #A GAG GAA AGG GGA GTA           958                                                                        Leu Ser Ser Ser Ile Leu Ala Gly Glu Asp Pr - #o Glu Glu Arg Gly Val                305              - #   310              - #   315                           - - AAA CTT GGA TTG GGA GAT TTC ATT TTC TAC AG - #T GTT CTG GTT GGT AAA          1006                                                                        Lys Leu Gly Leu Gly Asp Phe Ile Phe Tyr Se - #r Val Leu Val Gly Lys            320                 3 - #25                 3 - #30                 3 -       #35                                                                               - - GCC TCA GCA ACA GCC AGT GGA GAC TGG AAC AC - #A ACC ATA GCC TGT         TTC     1054                                                                     Ala Ser Ala Thr Ala Ser Gly Asp Trp Asn Th - #r Thr Ile Ala Cys Phe                           340  - #               345  - #               350               - - GTA GCC ATA TTA ATT GGT TTG TGC CTT ACA TT - #A TTA CTC CTT GCC ATT          1102                                                                        Val Ala Ile Leu Ile Gly Leu Cys Leu Thr Le - #u Leu Leu Leu Ala Ile                        355      - #           360      - #           365                   - - TTC AAG AAA GCA TTG CCA GCT CTT CCA ATC TC - #C ATC ACC TTT GGG CTT          1150                                                                        Phe Lys Lys Ala Leu Pro Ala Leu Pro Ile Se - #r Ile Thr Phe Gly Leu                    370          - #       375          - #       380                       - - GTT TTC TAC TTT GCC ACA GAT TAT CTT GTA CA - #G CCT TTT ATG GAC CAA          1198                                                                        Val Phe Tyr Phe Ala Thr Asp Tyr Leu Val Gl - #n Pro Phe Met Asp Gln                385              - #   390              - #   395                           - - TTA GCA TTC CAT CAA TTT TAT ATC TAGCATATTT GC - #GGTTAGAA TCCCATGGAT         1252                                                                        Leu Ala Phe His Gln Phe Tyr Ile                                                400                 4 - #05                                                     - - GTTTCTTCTT TGACTATAAC CAAATCTGGG GAGGACAAAG GTGATTTTCC TG -              #TGTCCACA   1312                                                                  - - TCTAACAAAG TCAAGATTCC CGGCTGGACT TTTGCAGCTT CCTTCCAAGT CT -             #TCCTGACC   1372                                                                  - - ACCTTGCACT ATTGGACTTT GGAAGGAGGT GCCTATAGAA AACGATTTTG AA -             #CATACTTC   1432                                                                  - - ATCGCAGTGG ACTGTGTCCC TCGGTGCAGA AACTACCAGA TTTGAGGGAC GA - #GGTC            1488                                                                        - -  - - (2) INFORMATION FOR SEQ ID NO:4:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 407 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -                   - #(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:               - - Gln Val Val Glu Gln Asp Glu Glu Glu Asp Gl - #u Glu Leu Thr Leu Lys         1               5 - #                 10 - #                 15               - - Tyr Gly Ala Lys His Val Ile Met Leu Phe Va - #l Pro Val Thr Leu Cys                    20     - #             25     - #             30                   - - Met Val Val Val Val Ala Thr Ile Lys Ser Va - #l Ser Phe Tyr Thr Arg                35         - #         40         - #         45                       - - Lys Asp Gly Gln Leu Ile Tyr Thr Pro Phe Th - #r Glu Asp Thr Glu Thr            50             - #     55             - #     60                           - - Val Gly Gln Arg Ala Leu His Ser Ile Leu As - #n Ala Ala Ile Met Ile        65                 - # 70                 - # 75                 - # 80        - - Ser Val Ile Val Val Met Thr Ile Leu Leu Va - #l Val Leu Tyr Lys Tyr                        85 - #                 90 - #                 95               - - Arg Cys Tyr Lys Val Ile His Ala Trp Leu Il - #e Ile Ser Ser Leu Leu                   100      - #           105      - #           110                   - - Leu Leu Phe Phe Phe Ser Phe Ile Tyr Leu Gl - #y Glu Val Phe Lys Thr               115          - #       120          - #       125                       - - Tyr Asn Val Ala Val Asp Tyr Ile Thr Val Al - #a Leu Leu Ile Trp Asn           130              - #   135              - #   140                           - - Phe Gly Val Val Gly Met Ile Ser Ile His Tr - #p Lys Gly Pro Leu Arg       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Leu Gln Gln Ala Tyr Leu Ile Met Ile Ser Al - #a Leu Met Ala Leu         Val                                                                                              165  - #               170  - #               175              - - Phe Ile Lys Tyr Leu Pro Glu Trp Thr Ala Tr - #p Leu Ile Leu Ala Val                   180      - #           185      - #           190                   - - Ile Ser Val Tyr Asp Leu Val Ala Val Leu Cy - #s Pro Lys Gly Pro Leu               195          - #       200          - #       205                       - - Arg Met Leu Val Glu Thr Ala Gln Glu Arg As - #n Glu Thr Leu Phe Pro           210              - #   215              - #   220                           - - Ala Leu Ile Tyr Ser Ser Thr Met Val Trp Le - #u Val Asn Met Ala Glu       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Gly Asp Pro Glu Ala Gln Arg Arg Val Ser Ly - #s Asn Ser Lys Tyr         Asn                                                                                              245  - #               250  - #               255              - - Ala Glu Ser Thr Glu Arg Glu Ser Gln Asp Th - #r Val Ala Glu Asn Asp                   260      - #           265      - #           270                   - - Asp Gly Gly Phe Ser Glu Glu Trp Glu Ala Gl - #n Arg Asp Ser His Leu               275          - #       280          - #       285                       - - Gly Pro His Arg Ser Thr Pro Glu Ser Arg Al - #a Ala Val Gln Glu Leu           290              - #   295              - #   300                           - - Ser Ser Ser Ile Leu Ala Gly Glu Asp Pro Gl - #u Glu Arg Gly Val Lys       305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - Leu Gly Leu Gly Asp Phe Ile Phe Tyr Ser Va - #l Leu Val Gly Lys         Ala                                                                                              325  - #               330  - #               335              - - Ser Ala Thr Ala Ser Gly Asp Trp Asn Thr Th - #r Ile Ala Cys Phe Val                   340      - #           345      - #           350                   - - Ala Ile Leu Ile Gly Leu Cys Leu Thr Leu Le - #u Leu Leu Ala Ile Phe               355          - #       360          - #       365                       - - Lys Lys Ala Leu Pro Ala Leu Pro Ile Ser Il - #e Thr Phe Gly Leu Val           370              - #   375              - #   380                           - - Phe Tyr Phe Ala Thr Asp Tyr Leu Val Gln Pr - #o Phe Met Asp Gln Leu       385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - Ala Phe His Gln Phe Tyr Ile                                                               405                                                             - -  - - (2) INFORMATION FOR SEQ ID NO:5:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 110 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:5:                - - CTATACGAAG NGCAGAGAAA TAAGGCCTAC TTCACAAGCG CCTTCCCCCG TA -              #ATGATATC     60                                                                  - - ATCTCAACTT AGTATTATAC CCACACCCAC CCAAGAATAG GGTTTAAAAA  - #                  110                                                                         - -  - - (2) INFORMATION FOR SEQ ID NO:6:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 210 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:6:                 - - CTCTATTGGT CTGAACTGTT CTTTCACGTT TCCCATTTCC CTGTGGCTCA CT -              #GTGCTTAC     60                                                                  - - AATCACTGCT GTGGAATCAT GATACCACTT TTAGCTCTTT GTATCTTCCT TC -             #AGTGTATT    120                                                                  - - TTTGTTTTTC AAGAGTAAGT AGATTTTAAC TGGACAACTT TGAGTACTGA CA -             #TCATTGAT    180                                                                  - - AAATAAACTG GCTTGTGGTT TCAATAAAAA         - #                  - #               210                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:7:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 373 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:7:                 - - CACACCCGAG CAAAACTGTT TATTCTTGAG AAGTTCCATC TTCATTTCTG CC -              #ACAGTTGG     60                                                                  - - AACTTCCCGA GGAAGGAAGG AGGCCTGAGG TTTTGCACAA TCTGTTTCAG AG -             #CCTGTTTA    120                                                                  - - GACTCAAACC TATGCTTCCC TTGGCAGCAG AATACACTTA ACCTAAAGCA GT -             #ATTTGGAG    180                                                                  - - TTGAGAAAAA CCTGGTGGGG TAAGTGAATA TGTACTGTTT GGTAGGGTAG GT -             #AGAGAAGC    240                                                                  - - TGTGCTTTGA CCCTGTGATT CCATCTTTTT CTACCTTCTA TGATGGTGAT GA -             #AGCTAGAT    300                                                                  - - ACCCCTAGGG AAGAAAGAAG GACTGGGTTT AGCAAAAATG ATTTGGTAAA TA -             #AAGTTTAT    360                                                                  - - TTGAACACAA AAA              - #                  - #                       - #     373                                                                   - -  - - (2) INFORMATION FOR SEQ ID NO:8:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 378 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:8:                 - - CTGAGGACCT TTTGTCTGAG AATCAGTAGT GTTTTAAGGT GCTGATATCG AA -              #TTAATGAA     60                                                                  - - GTAAAGTTGT TGATGGTGGT GAAACACCGT AGGGCATGTG GTTCAAAGAG AA -             #GCAGGAGG    120                                                                  - - GCAAGGGAAA GTTACCCTGA TCTTAGTTTG TAGCTTATGA CTTATTTAAT GA -             #ATGGATGC    180                                                                  - - CCAGCCAAGC TCAGAGTAGG CGCCCAAAGC ATTGTGGAGT AGTTTCCTGT TT -             #TGTCTTTT    240                                                                  - - TTTTTTTTTT TTTTTAAGCC ATGACATCCC AGAAGAGGAC AGTGAATTAC TC -             #CTAGGTCG    300                                                                  - - GCTCTTATAG AGTGGCCATA GTGTTCTGTC AAAACACTTG CTTCCATTTT CA -             #GAGATAAA    360                                                                  - - AATCATTGAT TACAAAAA             - #                  - #                       - # 378                                                                   - -  - - (2) INFORMATION FOR SEQ ID NO:9:                                      - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 270 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:9:                 - - TCAGGTGATG ACCGTCCGCT CCTAGTTCAC TGCTAGCTCA GCCTGAGGTT GC -              #AGACTGGT     60                                                                  - - CTGAAGGTGT ACAGGTGCCC TCTGTGCCTA TTCAGCAATT CCCTACTGAA GA -             #CTGGAGCG    120                                                                  - - CTCAGCCTGC CACGAACTGG ACTGCAGCTC CACTGCTCAG GCCAACTGAA TG -             #GGTAGGAG    180                                                                  - - CAACCACTGA CTGGTCTAAG CTGTTCTTGC ATAGGCTCTT AAGCAGCATG GA -             #AAAATGGT    240                                                                  - - TGATGGAAGA TAAACATCAG TTTCTAAAAA         - #                  - #               270                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:10:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 160 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:10:                - - AGTTCTAAGG CTGCTGCTAA TTACANNNNN NNNNNNNNNN GCTGACCTAG AA -              #GCAGCACC     60                                                                  - - ATTCCCATTT CCTCAGTACC CACAAAGTGC AGCCCACATT GGAGCCCCAG AC -             #ACCCTCT     120                                                                  - - GCAGCCATTG ACTGCAACTT GTTCTTTTGC CCATTAAAAA     - #                       - #   160                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:11:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 270 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:11:                - - AAGAGAGTGA AACAGCCACC TGTGTCACTG TGCCCGTCCA TGCTGACCTG TG -              #TTCCTCCC     60                                                                  - - CAGTCTCTTC TTGTTCCAGA GAGGTGGGGC TGATGTCTCC ATCTCTGTCT CA -             #CTTTATGT    120                                                                  - - GCACTGAGCT GCAACTTCTT ACTTCCCTAC TGAAAATAGA TCTGAATACG AT -             #TGTTCTC     180                                                                  - - AATATTGCTA TGAGAGGTTG ATGATTAATT AAATAAGTCA ATTCCTGGAA GT -             #GAGAGAGC    240                                                                  - - AAATAAAGAC CTGAGAACCT TCCAGAAAAA         - #                  - #               270                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:12:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 160 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:12:                - - TCGCAGATAC AGCTGTCAGG CTGCCTCCTG CCTTTTCTTT TGTAAAGACA AG -              #ACCCTTGG     60                                                                  - - AGTTTTAATT CTGTTTTGTA CTTCCTGTGG GGCCTCCACT GCTTTTCTAT GG -             #GAGACACT    120                                                                  - - CTTAATTTAA CAGATGTGTA TATTTTGAAA CTCTGAAAAA     - #                       - #   160                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:13:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 250 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:13:                - - GTCAGTTCGA TCGGCTCTAG TAGCCTGAGC ACTCATGCAG TCGCATGGCT CT -              #GTGTCTCT     60                                                                  - - CTGGTCTTGT ACTTGGTGCA ATAGCAACTT CCCTACCCGT GCATTCCATC TT -             #TCATGTTG    120                                                                  - - TGTAAAGTTC TTCACTTTTT TCTCTGAGGG CTGGGGGTTG GGGGAGTCAG CA -             #TGATTATA    180                                                                  - - TTTTAATGTA GAAAATGTGA CATCTGGATA TAAAATGAAG ATAAATGTTA AA -             #TTAAATGG    240                                                                  - - ACCTTAAAAA                - #                  - #                       - #       250                                                                   - -  - - (2) INFORMATION FOR SEQ ID NO:14:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 270 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:14:                - - AAGTGTATCT TACTGTGCCT GTCAGGTTAC AAACTAGTGC GTTGACGCAC AG -              #TGTCCAAG     60                                                                  - - TTATTAGAGC CCTTGTTAGC CAGACCCAGG TGTCCTGGTC ACCGTTTCAC CA -             #TCATGCTT    120                                                                  - - TGATGTTCCC CTGTCTTTCC CTCTTCTGCT CTCAAGAGCA AAGGTTAATT AA -             #GGTGCAAA    180                                                                  - - GATGAAGTCA CTGTAAACTA ATCTGTCATT GTTTTTGCCT TCCTTTTCTT TT -             #TCAGTGCA    240                                                                  - - GAAATTAAAA GTAAGTATAA AGCACAAAAA         - #                  - #               270                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:15:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 200 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:15:                - - TTGCAAGAAG TCAGAACNGG ATGGCTGGGT CTCCCCCTAC CTCTTCCAGC TC -              #CCACAATT     60                                                                  - - TTNCCATGAT GAGGTAGCTT CTCCCTGGGC TCTCCTTCTT GCCTACCCTG TC -             #TCCTGGGA    120                                                                  - - TCAGAGGGTA GTACAGAAGC CCTGACTCAT GCCTTGAGTA CATACCATAC AG -             #CAAATAAN    180                                                                  - - TGGTAGCAAA ACATTAAAAA            - #                  - #                       - #200                                                                   - -  - - (2) INFORMATION FOR SEQ ID NO:16:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 362 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:16:                - - AAGGAAGTGA AATCAAAGAC AGGCAGCCCG GCACCAGGCC TGAAACCAGC CC -              #TGGGCCTG     60                                                                  - - CCTGGCCTAA AGCTAGTAGT TAAAAATCAA CTTACGACTT AGAACCTGAT GT -             #TATCCGTA    120                                                                  - - GATTCCAAGC ATTGTATAAA AAAATTGTGA AACTCCCTGT TGTGTTCTGT AC -             #CAGTGCAT    180                                                                  - - GAAACCCCTG TCACATATCC CCTAGATTGC TCAATCAATC NCGACCCTTT CA -             #TGTGAAAT    240                                                                  - - CTTTAGTGTT GTGAGCCCTN AAAAGGGACA GAAATTGTGC ACTTGAGGAG CT -             #CAGATTTT    300                                                                  - - AAGGCTGTAG CTTGCCGATG CTCCCAGCTG AATAAAGCCC TTCCTTCNAC AA -             #CTCTGAAA    360                                                                  - - AA                  - #                  - #                  - #                  362                                                                   - -  - - (2) INFORMATION FOR SEQ ID NO:17:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 344 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:17:                - - ACCATGGATT CATGGTTTAT TTTATTCAGT GAGTTATAAT TCATTAATAT TG -              #TTATTAAA     60                                                                  - - AATTTGTTTT TCTTTTAAGA AATGTTATAT TTTGACAACT TCAGACTTAC AG -             #AAAGATTA    120                                                                  - - TAAGAGGTAG NNCAAATAAT TTTTGGATAT TATTCCCCAA ATGTTAACAT TT -             #TACTGCAT    180                                                                  - - TTACTTTATC CTTTCTCCCC CTTCTCCTCC TGTCTTTCTA GATGAATATG AA -             #TATAGGTA    240                                                                  - - CTTAATACAG ATTTTTTTTC TAAACTGTTT GTAGGTTGCA GACACGATGC CT -             #CTTTATTT    300                                                                  - - CTAAATAATG TGTATTTCCT AAATAAAAGG AATTACCTTA AAAA   - #                       - #344                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:18:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 210 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:18:                - - GTGACTGTGT ACTCTGCTGC TGCCGCCCTG CCCCAGAGCT CTCCTTGGCT GC -              #GTCTGGCC     60                                                                  - - GGCTCTCATG GTACTTCCTC TGTGAACTGT GTGTGAATCT GCTTTTCCTC TG -             #CTTCGGAG    120                                                                  - - GAAATTGTAA ATCCTGTGTT TCATTACTTG AATGTAGTTA TCTATTGAAA AT -             #ATATATTA    180                                                                  - - TATACATAGA CATATATATA TATATAAAAA         - #                  - #               210                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:19:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 310 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:19:                - - ACTCGATCTC TCACTAGACT GGCTGAAGTC CTACGTTCAG TGAAGATAAC TA -              #AGTCCTGC     60                                                                  - - TTTCTCAGTA CGCATTGCGG GTTTTACCAT TCATCCTGTC TAAGGTCCTG GG -             #TTTGGTGT    120                                                                  - - GAGCTTGGCG GCTGGTGGGT GGGGTTTTCA AGTGGGTCAC GGCGCTCTCG GC -             #AGCCGGGG    180                                                                  - - ATGCGTGTCC GCACTGACAG CCTGTGAGAG TGCTCGGCCT AACCTTAGAA CA -             #CATTGTAA    240                                                                  - - CTGAATACAG TGTTTTCAAT TTGTACAGAA TAGTTAGNAT ATTCTATTAA AG -             #TGGTGAAA    300                                                                  - - CATTGAAAAA                - #                  - #                       - #       310                                                                   - -  - - (2) INFORMATION FOR SEQ ID NO:20:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 338 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:20:                - - GGGGCACCCT CCCTGGCCAC ACGCCTGTTC CCAGCAAGTG CTGAAACTCA CT -              #AGACCGTC     60                                                                  - - TGCCTGTTTC GAAATGGGGA AAGCCGTGCG TGCGCGTTAT TTATTTAAGT GC -             #GCCTGTGT    120                                                                  - - GCGCGGGTGT GGGAGCACAC TTTGCAAAGC CACAGCGTTT CTGGTTTTGG GT -             #GTACAGTC    180                                                                  - - TTGTGTGCCT GGCGAGAAGA ATATTTTCTA TTTTTTTAAG TCATTTCATG TT -             #TCTGTCTG    240                                                                  - - GGGAAGGCAA GTTAGTTAAG TATCACTGAT GTGGGTTGAG ACCAGCACTC TG -             #TGAAACCT    300                                                                  - - TGAAATGAGA AGTAAAGGCA GATGAAAAGA AAGAAAAA      - #                       - #    338                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:21:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 170 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:21:                - - TCTACTCGAA ACGCAGTACA CACTTTATCA GCCAGAGCTA GTCAGTCTGT GC -              #TCCTGGCT     60                                                                  - - ATAAGACCCA GCCTGAGATG GTCCCATCTG CAGGGCCCGC ACCAGTTGGA CA -             #GATGCCTC    120                                                                  - - CCCACCACCA ATTGCCAAAG GTCCAATAAA ATGCCTCAAC CACGGAAAAA  - #                  170                                                                         - -  - - (2) INFORMATION FOR SEQ ID NO:22:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 180 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:22:                - - CTGCCAGTTT CAGGCCTCGG TCCATAGAGA CACCACCACC ATGGCCAGTG AA -              #AGGTATAG     60                                                                  - - TCCTGCAGCA GCTGTCTCCT GGTGCAGGTG CCTGCCAGCC CACTGGATTG GG -             #ACGGGCCA    120                                                                  - - GGCTGGGCCA GGTCGGGGGC TCAGTCTGGG AGGTAATAAA AGCAGACCGA CA -             #CGCAAAAA    180                                                                  - -  - - (2) INFORMATION FOR SEQ ID NO:23:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 110 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:23:               - - GGCAAGCAGN TTCTGGTGGG TGTGTGGTGG TACCTCACTG TGGTTTTGGT TT -              #GCGTTTTC     60                                                                  - - CTCTATTTGC ACAAAATGAT ATTAAATATA TTTTATGCTT ATTAGTCATT  - #                  110                                                                         - -  - - (2) INFORMATION FOR SEQ ID NO:24:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 90 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:24:                - - CAGAAGGTCT GCCATGGAGT TGCAGTCATC ACGGTAGATG GCGTATGATT TT -              #GCTGAATT     60                                                                  - - TTAAATAAAA TGAAAACCAT AAATTAAAAA         - #                  - #                90                                                                      - -  - - (2) INFORMATION FOR SEQ ID NO:25:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 433 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:25:                - - TAAAATTTCG GTTGGGCGAC CTCGGAGCAG AACCAACCTC CGAGCAGTAC AT -              #GCTAAGAC     60                                                                  - - TTCACCAGTC AAAGCGAACT ACTATACTCA ATTGATCCAA TAACTTGACC AA -             #CGGAACAA    120                                                                  - - GTTACCCTAG GGATAACAGC GCAATCCTAT TCTAGAGTCC ATATCAACAA TA -             #GGGTTTAC    180                                                                  - - GACCTCGATG TTGGATCAGG ACATCCCGAT GGTGCAGCCG CTATTAAAGG TT -             #CGTTTGTT    240                                                                  - - CAACGATTAA AGTCCTACGT GATCTGAGTT CAGACCGGAG TAATCCAGGT CG -             #GTTTCTAT    300                                                                  - - CTACTTCAAA TTCCTCCCTG TACGAAAGGA CAAGAGAAAT AAGGCCTACT TC -             #ACAAAGCG    360                                                                  - - CCTTCCCCGT AAATGATATC ATCTCAACTT AGTATTATAC CCACACCCAC CC -             #AAGAACAG    420                                                                  - - GGTTTGTTAA AAA              - #                  - #                       - #     433                                                                   - -  - - (2) INFORMATION FOR SEQ ID NO:26:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 366 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:26:                - - ATTACAATTC AGTTTCTGTG ACATCTTTTT AAACCACTGG AGGAAAAATG AG -              #ATATTCTC     60                                                                  - - TAATTTATTC TTCTATAACA CTCTATATAG AGCTATGTGA GTNCTAATCA CA -             #TTGAATAA    120                                                                  - - TAGTTATAAA ATTATTGTAT AGACATCTGC TTCTTAAACA GNTTGTGAGT TC -             #TTTGAGAA    180                                                                  - - ACAGCGTGGA TTTTACTTAT CTGTGTATTC ACAGAGCTTA GCNCAGTGCC TG -             #GTAATGAG    240                                                                  - - CAAGCATACT TGCCATTACT TTTCCTTCCC ACTCTCTCCA ACATCACATT CA -             #CTTTAAAT    300                                                                  - - TTTTCTGTAT ATAGAAAGGA AAACTAGCCT GGGCAACATG ATGAAACCCC AT -             #CTCCACTG    360                                                                  - - CAAAAA                 - #                  - #                  -      #          366                                                                   - -  - - (2) INFORMATION FOR SEQ ID NO:27:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 200 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:27:                - - TAAGTAGTAG AAGCTGTTAA TATACATGCA TCGTAACCTC AGAAGCAAGA GA -              #ATGTTTTG     60                                                                  - - TGGACCACTT TGGTTTTCTT TTTTGCGTGT GGCAGTTTTA AGTTATTAGT TT -             #TTAAAATC    120                                                                  - - AGTACTTTTT AATGGAAACA ACTTGACCAA AAATTTGTCA CAGAATTTTG AG -             #ACCCATTA    180                                                                  - - AAAAAGTTAA ATGAGAAAAA            - #                  - #                       - #200                                                                   - -  - - (2) INFORMATION FOR SEQ ID NO:28:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 2276 base - #pairs                                                 (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: double                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:28:                - - CTCTACCGGA TCCACTATTA CGGGGGGGGG GGGGGGGGCT GGACCGCGGC GG -              #CAGAAACA     60                                                                  - - GGCATTTCCA GCAGTGAGGA GACAGCCAGA AGCAAGCTTT TGGAGCTGAA GG -             #AACCTGAG    120                                                                  - - ACAGAAGCTA GTCCCCCCTC TGAATTTTAC TGATGAAGAA ACTGAGGCCA CA -             #GAGCTAAA    180                                                                  - - GTGACTTTTC CCAAGGTCGC CCAGCGAGGA CGTGGGACTT CTCAGACGTC AG -             #GAGAGTGA    240                                                                  - - TGTGAGGGAG CTGTGTGACC ATAGAAAGTG ACGTGTTAAA AACCAGCGCT GC -             #CCTCTTTG    300                                                                  - - AAAGCCAGGG AGCATCATTC ACTTAGCCTG CTGAGAAGAA GAAACCAAGT GT -             #CCGGGATT    360                                                                  - - CAGACCTCTC TGCGGCCCCA AGTGTTCGTG GTGCTTCCAG AGGCAGGGCT AT -             #GCTCACAT    420                                                                  - - TCATGGCCTC TGACAGCGAG GAAGAAGTGT GTGATGAGCG GACGTCCCTA AT -             #GTCGGCCG    480                                                                  - - AGAGCCCCAC GCCGCGCTCC TGCCAGGAGG GCAGGCAGGG CCCAGAGGAT GG -             #AGAGAACA    540                                                                  - - CTGCCCAGTG GAGAAGCCAG GAGAACGAGG AGGACGGTGA GGAGGACCCT GA -             #CCGCTATG    600                                                                  - - TCTGTAGTGG GGTTCCCGGG CGGCCGCCAG GCCTGGAGGA AGAGCTGACC CT -             #CAAATACG    660                                                                  - - GAGCGAAGCA CGTGATCATG CTGTTTGTGC CTGTCACTCT GTGCATGATC GT -             #GGTGGTAG    720                                                                  - - CCACCATCAA GTCTGTGCGC TTCTACACAG AGAAGAATGG ACAGCTCATC TA -             #CACGCCAT    780                                                                  - - TCACTGAGGA CACACCCTCG GTGGGCCAGC GCCTCCTCAA CTCCGTGCTG AA -             #CACCCTCA    840                                                                  - - TCATGATCAG CGTCATCGTG GTTATGACCA TCTTCTTGGT GGTGCTCTAC AA -             #GTACCGCT    900                                                                  - - GCTACAAGTT CATCCATGGC TGGTTGATCA TGTCTTCACT GATGCTGCTG TT -             #CCTCTTCA    960                                                                  - - CCTATATCTA CCTTGGGGAA GTGCTCAAGA CCTACAATGT GGCCATGGAC TA -             #CCCCACCC   1020                                                                  - - TCTTGCTGAC TGTCTGGAAC TTCGGGGCAG TGGGCATGGT GTGCATCCAC TG -             #GAAGGGCC   1080                                                                  - - CTCTGGTGCT GCAGCAGGCC TACCTCATCA TGATCAGTGC GCTCATGGCC CT -             #AGTGTTCA   1140                                                                  - - TCAAGTACCT CCCAGAGTGG TCCGCGTGGG TCATCCTGGG CGCCATCTCT GT -             #GTATGATC   1200                                                                  - - TCGTGGCTGT GCTGTGTCCC AAAGGGCCTC TGAGAATGCT GGTAGAAACT GC -             #CCAGGAGA   1260                                                                  - - GAAATGAGCC CATATTCCCT GCCCTGATAT ACTCATCTGC CATGGTGTGG AC -             #GGTTGGCA   1320                                                                  - - TGGCGAAGCT GGACCCCTCC TCTCAGGGTG CCCTCCAGCT CCCCTACGAC CC -             #GGAGATGG   1380                                                                  - - AAGACTCCTA TGACAGTTTT GGGGAGCCTT CATACCCCGA AGTCTTTGAG CC -             #TCCTTGA    1440                                                                  - - CTGGCTACCC AGGGGAGGAG CTGGAGGAAG AGGAGGAAAG GGGCGTGAAG CT -             #TGGCCTCG   1500                                                                  - - GGGACTTCAT CTTCTACAGT GTGCTGGTGG GCAAGGCGGC TGCCACGGGC AG -             #CGGGGACT   1560                                                                  - - GGAATACCAC GCTGGCCTGC TTCGTGGCCA TCCTCATTGG CTTGTGTCTG AC -             #CCTCCTGC   1620                                                                  - - TGCTTGCTGT GTTCAAGAAG GCGCTGCCCG CCCTCCCCAT CTCCATCACG TT -             #CGGGCTCA   1680                                                                  - - TCTTTTACTT CTCCACGGAC AACCTGGTGC GGCCGTTCAT GGACACCCTG GC -             #CTCCCATC   1740                                                                  - - AGCTCTACAT CTGAGGGACA TGGTGTGCCA CAGGCTGCAA GCTGCAGGGA AT -             #TTTCATTG   1800                                                                  - - GATGCAGTTG TATAGTTTTA CACTCTAGTG CCATATATTT TTAAGACTTT TC -             #TTTCCTTA   1860                                                                  - - AAAAATAAAG TACGTGTTTA CTTGGTGAGG AGGAGGCAGA ACCAGCTCTT TG -             #GTGCCAGC   1920                                                                  - - TGTTTCATCA CCAGACTTTG GCTCCCGCTT TGGGGAGCGC CTCGCTTCAC GG -             #ACAGGAAG   1980                                                                  - - CACAGCAGGT TTATCCAGAT GAACTGAGAA GGTCAGATTA GGGCGGGGAG AA -             #GAGCATCC   2040                                                                  - - GGCATGAGGG CTGAGATGCG CAAAGAGTGT GCTCGGGAGT GGCCCCTGGC AC -             #CTGGGTGC   2100                                                                  - - TCTGGCTGGA GAGGAAAAGC CAGTTCCCTA CGAGGAGTGT TCCCAATGCT TT -             #GTCCATGA   2160                                                                  - - TGTCCTTGTT ATTTTATTGC CTTTAGAAAC TGAGTCCTGT TCTTGTTACG GC -             #AGTCACAC   2220                                                                  - - TGCTGGGAAG TGGCTTAATA GTAATATCAA TAAATAGATG AGTCCTGTTA GA - #AAAA            2276                                                                        - -  - - (2) INFORMATION FOR SEQ ID NO:29:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 447 amino - #acids                                                 (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -                 (xi) - #SEQUENCE DESCRIPTION: SEQ ID NO:29:                - - Met Leu Thr Phe Met Ala Ser Asp Ser Glu Gl - #u Glu Val Cys Asp Glu       1               5   - #                10  - #                15                - - Arg Thr Ser Leu Met Ser Ala Glu Ser Pro Th - #r Pro Arg Ser Cys Gln                   20      - #            25      - #            30                    - - Glu Gly Arg Gln Gly Pro Glu Asp Gly Glu As - #n Thr Ala Gln Trp Arg               35          - #        40          - #        45                        - - Ser Gln Glu Asn Glu Glu Asp Gly Glu Glu As - #p Pro Asp Arg Tyr Val           50              - #    55              - #    60                            - - Cys Ser Gly Val Pro Gly Arg Pro Pro Gly Le - #u Glu Glu Glu Leu Thr       65                  - #70                  - #75                  - #80         - - Leu Lys Tyr Gly Ala Lys His Val Ile Met Le - #u Phe Val Pro Val Thr                       85  - #                90  - #                95                - - Leu Cys Met Ile Val Val Val Ala Thr Ile Ly - #s Ser Val Arg Phe Tyr                   100      - #           105      - #           110                   - - Thr Glu Lys Asn Gly Gln Leu Ile Tyr Thr Pr - #o Phe Thr Glu Asp Thr               115          - #       120          - #       125                       - - Pro Ser Val Gly Gln Arg Leu Leu Asn Ser Va - #l Leu Asn Thr Leu Ile           130              - #   135              - #   140                           - - Met Ile Ser Val Ile Val Val Met Thr Ile Ph - #e Leu Val Val Leu Tyr       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Lys Tyr Arg Cys Tyr Lys Phe Ile His Gly Tr - #p Leu Ile Met Ser         Ser                                                                                              165  - #               170  - #               175              - - Leu Met Leu Leu Phe Leu Phe Thr Tyr Ile Ty - #r Leu Gly Glu Val Leu                   180      - #           185      - #           190                   - - Lys Thr Tyr Asn Val Ala Met Asp Tyr Pro Th - #r Leu Leu Leu Thr Val               195          - #       200          - #       205                       - - Trp Asn Phe Gly Ala Val Gly Met Val Cys Il - #e His Trp Lys Gly Pro           210              - #   215              - #   220                           - - Leu Val Leu Gln Gln Ala Tyr Leu Ile Met Il - #e Ser Ala Leu Met Ala       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Leu Val Phe Ile Lys Tyr Leu Pro Glu Trp Se - #r Ala Trp Val Ile         Leu                                                                                              245  - #               250  - #               255              - - Gly Ala Ile Ser Val Tyr Asp Leu Val Ala Va - #l Leu Cys Pro Lys Gly                   260      - #           265      - #           270                   - - Pro Leu Arg Met Leu Val Glu Thr Ala Gln Gl - #u Arg Asn Glu Pro Ile               275          - #       280          - #       285                       - - Phe Pro Ala Leu Ile Tyr Ser Ser Ala Met Va - #l Trp Thr Val Gly Met           290              - #   295              - #   300                           - - Ala Lys Leu Asp Pro Ser Ser Gln Gly Ala Le - #u Gln Leu Pro Tyr Asp       305                 3 - #10                 3 - #15                 3 -       #20                                                                               - - Pro Glu Met Glu Asp Ser Tyr Asp Ser Phe Gl - #y Glu Pro Ser Tyr         Pro                                                                                              325  - #               330  - #               335              - - Glu Val Phe Glu Pro Pro Leu Thr Gly Tyr Pr - #o Gly Glu Glu Leu Glu                   340      - #           345      - #           350                   - - Glu Glu Glu Glu Arg Gly Val Lys Leu Gly Le - #u Gly Asp Phe Ile Phe               355          - #       360          - #       365                       - - Tyr Ser Val Leu Val Gly Lys Ala Ala Ala Th - #r Gly Ser Gly Asp Trp           370              - #   375              - #   380                           - - Asn Thr Thr Leu Ala Cys Phe Val Ala Ile Le - #u Ile Gly Leu Cys Leu       385                 3 - #90                 3 - #95                 4 -       #00                                                                               - - Thr Leu Leu Leu Leu Ala Val Phe Lys Lys Al - #a Leu Pro Ala Leu         Pro                                                                                              405  - #               410  - #               415              - - Ile Ser Ile Thr Phe Gly Leu Ile Phe Tyr Ph - #e Ser Thr Asp Asn Leu                   420      - #           425      - #           430                   - - Val Arg Pro Phe Met Asp Thr Leu Ala Ser Hi - #s Gln Leu Tyr Ile                   435          - #       440          - #       445                     __________________________________________________________________________ 

What is claimed is:
 1. A method of identifying an agent which is an inhibitor of improper chromosome segregation comprising the steps of:a) providing cells, referred to as tester cells, transfected with a plasmid suitable for reproduction in the tester cells, wherein the plasmid comprises a gene, referred to as a test gene, whose gene product causes chromosome missegregation and the appropriate control elements for expressing or over expressing the gene; b) exposing the tester cells to an agent being tested as an inhibitor of chromosome missegregation; c) incubating the tester cells under conditions suitable for the tester cells to reproduce, thereby producing progeny cells; d) assessing the number of aneuploid progeny cells or the number of progeny cells with a chromosome having a break or a translocation, wherein a lower frequency of aneuploid progeny cells or a lower frequency of progeny cells with a chromosome having a break or a translocation in the presence of the agent being tested than in the absence of the agent being tested is indicative that the agent is an inhibitor of improper chromosome segregation.
 2. The method of claim 1 wherein the tester cells are mammalian cells.
 3. The method of claim 2 wherein the mammalian cells are human cells.
 4. The method of claim 1 wherein:a) the tester cells comprise:i) a chromosome with a mutated centromere which makes the chromosome prone to improper segregation; and ii) a gene on the chromosome with the mutated centromere, referred to as a marker gene, whose gene product gives a quantifiable indication of the number of chromosomes with the mutated centromere present in the tester cell; b) the number of aneuploid progeny cells is determined by quantifying the indication given by the marker gene product; and c) the tester cells are yeast cells.
 5. The method of claim 4 wherein the marker gene encodes a gene product which enhances or suppresses the expression of a second marker gene, wherein the second marker gene encodes a gene product which gives a quantifiable indication of the number of chromosomes with the mutated centromere present in the test cell.
 6. The method of claim 4 wherein the chromosome of (a)(i) comprises two marker genes, wherein the first marker gene is sup 11 and the second marker gene is ade2.
 7. The method of claim 1 wherein the test gene comprises a polynucleotide represented by SEQ ID NO: 1, or a polynucleotide which comprises at least 90 nucleotides and is contained in the test gene.
 8. The method of claim 1 wherein the test gene comprises a polydeoxynucleotide represented by SEQ ID NO: 3, or a polydeoxynucleotide which comprises at least 90 nucleotides and is contained in the test gene.
 9. The method of claim 1 wherein the test gene comprises a polydeoxynucleotide represented by SEQ ID NO: 27, or a polydeoxynucleotide which comprises at least 90 nucleotides and is contained in the test gene.
 10. The method of claim 1 wherein the test gene comprises a polydeoxynucleotide represented by a SEQ ID NO selected from the group consisting of: SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, and polydeoxynucleotides which comprise at least 90 nucleotides and are contained in the test gene.
 11. The method of claim 2 wherein the test gene encodes an Apolipoprotein E.
 12. The method of claim 1 wherein the test gene comprises a polydeoxynucleotide represented by a SEQ ID NO selected from the group consisting of: SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ BD NO: 12, SEQ ID NO: 13, and SEQ ID NO:
 14. 